Skip to content

Leetcode

LeetCode-Google-85

Get Well Prepared for Google Interview

  • 929. Unique Email Addresses https://youtu.be/OnX5duNfKrw
  • 975. Odd Even Jump
  • 482. License Key Formatting https://youtu.be/kcS4vdrHOxQ
  • 904. Fruit Into Baskets https://youtu.be/tklM87rwiJQ

Arrys and Strings

  • 3. Longest Substring Without Repeating Characters https://youtu.be/4l8rH6piISc
  • 11. Container With Most Water https://youtu.be/PExFVKqTtpo
  • 15. 3Sum https://youtu.be/8uIbr4JRFfw
  • 31. Next Permutation https://youtu.be/jw9C0FaozzY
  • 43. Multiply Strings https://youtu.be/2FnEBrTJLvo
  • 48. Rotate Image https://youtu.be/1fRT6HHYMSI
  • 55. Jump Game https://youtu.be/bvCxdTHQvPg
  • 66. Plus One https://youtu.be/u2oSZBLjN_I
  • 76. Minimum Window Substring https://youtu.be/Xdcwzs1Eigs
  • 158. Read N Characters Given Read4 II - Call multiple times https://youtu.be/oxC0h_DdHgU
  • 159. Longest Substring with At Most Two Distinct Characters https://youtu.be/UNT298i-pnk
  • 163. Missing Ranges https://youtu.be/645L5uiLQ8I
  • 681. Next Closest Time https://youtu.be/NCxvNXyxOT0
  • 809. Expressive Words https://youtu.be/xQcqikMVOAI
  • 833. Find And Replace in String https://youtu.be/EcTcmkUeKA8
  • 849. Maximize Distance to Closest Person https://youtu.be/7vXfkN7ynfI
  • 20. Valid Parentheses https://youtu.be/trp7wvvKgj8
  • 23. Merge k Sorted Lists https://youtu.be/kXtQMtQ65z4
  • 42. Trapping Rain Water https://youtu.be/DPLaaCgqMNo
  • 215. Kth Largest Element in an Array https://youtu.be/PuUVWqt6sh4
  • 253. Meeting Rooms II https://youtu.be/1ewzuB-cz5A
  • 844. Backspace String Compare https://youtu.be/eMFVuhkLV5A
  • 857. Minimum Cost to Hire K Workers
  • 973. K Closest Points to Origin https://youtu.be/qBxovIOmdKU

Linked Lists

  • 2. Add Two Numbers https://youtu.be/uZGLP7FXdSE
  • 19. Remove Nth Node From End of List https://youtu.be/Jg096GV_YRA
  • 21. Merge Two Sorted Lists https://youtu.be/3jPyssUjTNc
  • 138. Copy List with Random Pointer https://youtu.be/3g3ldlJJl1U

Trees and Graphs

  • 124. Binary Tree Maximum Path Sum https://youtu.be/d4OdUVsjWAk
  • 127. Word Ladder https://youtu.be/oDqZwuQDf-8
  • 200. Number of Islands https://youtu.be/yhvEyl05SPo
  • 210. Course Schedule II https://youtu.be/g8FaK2-g1Ug
  • 222. Count Complete Tree Nodes https://youtu.be/pCIUFk-Vh0c
  • 329. Longest Increasing Path in a Matrix https://youtu.be/UirUNzm0p8M
  • 394. Decode String https://youtu.be/Bz8R_Kx2YAs
  • 399. Evaluate Division https://youtu.be/eEM7FId861U
  • 543. Diameter of Binary Tree https://youtu.be/ID7bAofTin0
  • 753. Cracking the Safe https://youtu.be/kfvjqzGLDTY
  • 489. Robot Room Cleaner https://youtu.be/UHK5TKLQOIM
  • 947. Most Stones Removed with Same Row or Column https://youtu.be/t0ooS4WlvJ8
  • 951. Flip Equivalent Binary Trees https://youtu.be/mRnar6_jbWw

Recursion

  • 425. Word Squares https://youtu.be/oFe3LvZhuuE ‼️
  • 247. Strobogrammatic Number II https://youtu.be/M2wKEpcpg7k ‼️
  • 212. Word Search II https://youtu.be/gWt1Z5DVWEQ ‼️
  • 351. Android Unlock Patterns
  • 17. Letter Combinations of a Phone Number https://youtu.be/TRNWgRYVxU0
  • 22. Generate Parentheses https://youtu.be/hp1zd0MInqU

Sorting and Searching

  • 4. Median of Two Sorted Arrays (Binary Search Implement so Hard!!!)
  • Binary Search Approach (Implement so Hard!!!)
  • Two Pointers Approach https://youtu.be/AZl3W4MVKD0
  • 34. Find First and Last Position of Element in Sorted Array https://youtu.be/5bXXgj0tk24
  • 56. Merge Intervals
  • 57. Insert Interval
  • 242. Valid Anagram https://youtu.be/2-nB7tpTjKo
  • 315. Count of Smaller Numbers After Self
  • 852. Peak Index in a Mountain Array https://youtu.be/1InUzTclKDE

Dynamic Programming

  • 5. Longest Palindromic Substring
  • 53. Maximum Subarray
  • 121. Best Time to Buy and Sell Stock
  • 152. Maximum Product Subarray
  • 322. Coin Change
  • 410. Split Array Largest Sum

Design

  • 146. LRU Cache
  • 155. Min Stack
  • 297. Serialize and Deserialize Binary Tree
  • 359. Logger Rate Limiter
  • 380. Insert Delete GetRandom O(1)
  • 642. Design Search Autocomplete System

Other

  • 7. Reverse Integer
  • 135. Candy
  • 205. Isomorphic Strings
  • 246. Strobogrammatic Number
  • 299. Bulls and Cows
  • 308. Range Sum Query 2D - Mutable
  • 731. My Calendar II
  • 771. Jewels and Stones
  • 777. Swap Adjacent in LR String
  • 843. Guess the Word
  • 939. Minimum Area Rectangle

NeetCode-150

Bit Manipulation

  • 7. Reverse Integer https://youtu.be/G75MJ2Mhayc
  • 371. Sum of Two Integers https://youtu.be/zWULGex4o94
  • 268. Missing Number https://youtu.be/28Dt58GoLe4
  • 190. Reverse Bits https://youtu.be/lkOuHN-VQIM
  • 338. Counting Bits https://youtu.be/WpG0vQo3aSY
  • 191. Number of 1 Bits https://youtu.be/ePnm49DdKKI
  • 136. Single Number https://youtu.be/uMfOCzPrVFs

Math & Geometry

  • 2013. Detect Squares https://youtu.be/0bsUP2tlkeM
  • 43. Multiply Strings https://youtu.be/zYAZfVyZtDM
  • 50. Pow(x, n) https://youtu.be/tcsP8U_gH4o
  • 66. Plus One https://youtu.be/9lKzq3XAwtI
  • 202. Happy Number https://youtu.be/SiGOX98n5kg
  • 73. Set Matrix Zeroes https://youtu.be/cdGlO44QVsw
  • 54. Spiral Matrix https://youtu.be/3GJGSwljdXQ
  • 48. Rotate Image https://youtu.be/Zi47Qc64Zes

Intervals

  • 1851. Minimum Interval to Include Each Query https://youtu.be/yzICp_Fqjsg
  • 253. Meeting Rooms II https://youtu.be/zE8_Jb5JHvY
  • 252. Meeting Rooms https://youtu.be/dCzcEppDa14
  • 435. Non-Overlapping Intervals https://youtu.be/KdgE1tr7Aek
  • 56. Merge Intervals https://youtu.be/ozHVCQ3zZFo
  • 57. Insert Interval https://youtu.be/OzRJBokoiek

Greedy

  • 678. Valid Parenthesis String https://youtu.be/Ng76PLOrk-Y
  • 763. Partition Labels https://youtu.be/uxmx5m7T_U0
  • 1899. Merge Triplets to Form Target Triplet https://youtu.be/q0IYzyJeedE
  • 846. Hand of Straights https://youtu.be/GoYeVytpaxM
  • 134. Gas Station https://youtu.be/xl3UztFLC-w
  • 45. Jump Game II https://youtu.be/GMEBL7hgfnA
  • 55. Jump Game https://youtu.be/P29vLV9RCg0
  • 53. Maximum Subarray https://youtu.be/c6kTnMmKEJQ

2-D Dynamic Programming

  • 10. Regular Expression Matching https://youtu.be/xSMksRLx3Rc
  • 312. Burst Balloons https://youtu.be/hdDknHmumwE
  • 72. Edit Distance https://youtu.be/OuW2d81vQWM
  • 115. Distinct Subsequences https://youtu.be/kaaAlGyToDA
  • 329. Longest Increasing Path in a Matrix https://youtu.be/oPWolhM9VXA
  • 97. Interleaving String https://youtu.be/-FmPBe1NF6w
  • 494. Target Sum https://youtu.be/RBa1f_RxvLY
  • 518. Coin Change 2 https://youtu.be/57gj680Krbg
  • 309. Best Time to Buy and Sell Stock with Cooldown https://youtu.be/_jEyxbB63Pk
  • 1143. Longest Common Subsequence https://youtu.be/I7RMRdwOw4s
  • 62. Unique Paths https://youtu.be/MD3devXa4sE

1-D Dynamic Programming

  • 416. Partition Equal Subset Sum https://youtu.be/I7RMRdwOw4s
  • 300. Longest Increasing Subsequence https://youtu.be/JuTncX_U7TI
  • 139. Word Break https://youtu.be/Psh9eIc3LzY
  • 152. Maximum Product Subarray https://youtu.be/bbRMgZXJbYU
  • 322. Coin Change https://youtu.be/Lpi4PGw0Hqs
  • 91. Decode Ways https://youtu.be/_DvPqLwOH_I
  • 647. Palindromic Substrings https://youtu.be/6AZVmhhzWs0
  • 5. Longest Palindromic Substring https://youtu.be/FzPa7RFLapE
  • 213. House Robber II https://youtu.be/qYV5OYABlYg
  • 198. House Robber https://youtu.be/cVXGfzpj7xQ
  • 746. Min Cost Climbing Stairs https://youtu.be/KLzmpTPiY4E
  • 70. Climbing Stairs https://youtu.be/quTkVXCvN_s

Advanced Graphs

  • 787. Cheapest Flights Within K Stops https://youtu.be/HjW7BgIQGUo
  • 269. Alien Dictionary https://youtu.be/IM6T9K-lAfo
  • 778. Swim in Rising Water https://youtu.be/YEWl6kYZYHk
  • 743. Network Delay Time https://youtu.be/qBnGGDMNJs0
  • 1584. Min Cost to Connect All Points https://youtu.be/g-bWPitJe5Q
  • 332. Reconstruct Itinerary https://youtu.be/An-3XjlfSxk

Graphs

  • 127. Word Ladder https://youtu.be/_4CA5h70MFg
  • 261. Graph Valid Tree https://youtu.be/_8nYk6QYIKw
  • 323. Number of Connected Components in an Undirected Graph https://youtu.be/fEPUzKfhTdw
  • 684. Redundant Connection https://youtu.be/CdvSCPD3L58
  • 210. Course Schedule II https://youtu.be/1m2KBCovZtY
  • 207. Course Schedule https://youtu.be/kINSe_qxnUM
  • 286. Walls and Gates https://youtu.be/gRbd3oB6wrI
  • 994. Rotting Oranges https://youtu.be/mrqyeHvLtiw
  • 130. Surrounded Regions https://youtu.be/Su9UnEX-F0g
  • 417. Pacific Atlantic Water Flow https://youtu.be/8LcIHuC0uMc
  • 695. Max Area of Island https://youtu.be/_wdIuL_6IRU
  • 133. Clone Graph https://youtu.be/lruPeH0zfcw
  • 200. Number of Islands https://youtu.be/3-RQp3QdCeM

Tries

  • 212. Word Search II https://youtu.be/b4e9UEVC3a4
  • 211. Design Add and Search Words Data Structure https://youtu.be/jkW8HUrvo9k
  • 208. Implement Trie (Prefix Tree) https://youtu.be/p6ukG71c5mg

Backtracking

  • 51. N-Queens https://youtu.be/KfDdyfawRs8
  • 17. Letter Combinations of a Phone Number https://youtu.be/zHit5TF8TBU
  • 131. Palindrome Partitioning https://youtu.be/dVS0kTqpIpk
  • 79. Word Search https://youtu.be/NKV5623if8c
  • 40. Combination Sum II https://youtu.be/k6EMen8LB7I
  • 90. Subsets II https://youtu.be/zeV_YNds8No
  • 46. Permutations https://youtu.be/npyO0goeHiE
  • 39. Combination Sum https://youtu.be/-3k4ywlRRxY
  • 78. Subsets https://youtu.be/GSZjthjG_Ck

Heap / Priority Queue

  • 295. Find Median from Data Stream https://youtu.be/cZ4rpUohVPo
  • 355. Design Twitter https://youtu.be/bayWF4JBsiI
  • 621. Task Scheduler https://youtu.be/7lzRGcHYazI
  • 215. Kth Largest Element in an Array https://youtu.be/ig-EQ6obRHM
  • 973. K Closest Points to Origin https://youtu.be/R-uU_yqWhIc
  • 1046. Last Stone Weight https://youtu.be/RoKyynj10zs
  • 703. Kth Largest Element in a Stream https://youtu.be/jjjcPmSuv5s

Trees

  • 297. Serialize and Deserialize Binary Tree https://youtu.be/-wCBoxB2Jtk
  • 124. Binary Tree Maximum Path Sum https://youtu.be/2BlWblqS-Pk
  • 105. Construct Binary Tree from Preorder and Inorder Traversal https://youtu.be/mrs1iaMn8wo
  • 230. Kth Smallest Element in a BST https://youtu.be/YHQXeSinnu8
  • 98. Validate Binary Search Tree https://youtu.be/TADCpxISg8o
  • 1448. Count Good Nodes in Binary Tree https://youtu.be/3wLTv32x_m8
  • 199. Binary Tree Right Side View https://youtu.be/Xv8LDRg4Uak
  • 102. Binary Tree Level Order Traversal https://youtu.be/dmEib-2Xrfw
  • 235. Lowest Common Ancestor of a Binary Search Tree https://youtu.be/35142ZvdJBY
  • 572. Subtree of Another Tree https://youtu.be/WY98XkdYSBc
  • 100. Same Tree https://youtu.be/28XmzR7O1GY
  • 110. Balanced Binary Tree https://youtu.be/s88-WdCU9OQ
  • 543. Diameter of a Binary Tree https://youtu.be/hkiGsyUYsxs
  • 104. Maximum Depth of Binary Tree https://youtu.be/YH_L6P1attM
  • 226. Invert Binary Tree https://youtu.be/n01ogAn19bY

Linked List

  • 25. Reverse Nodes in k-Group https://youtu.be/LW7Il65S6NU
  • 23. Merge k Sorted Lists https://youtu.be/q20QxWP5fCw
  • 146. LRU Cache https://youtu.be/igB6Z3FqoEA
  • 287. Find the Duplicate Number https://youtu.be/dJ2If-D0HPc
  • 141. Linked List Cycle https://youtu.be/EhUg5nMNjtY
  • 2. Add Two Numbers https://youtu.be/mNVLlXg_MGI
  • 138. Copy List with Random Pointer https://youtu.be/kxyui8GTy_0
  • 19. Remove Nth Node From End of List https://youtu.be/BIeLoOQHla0
  • 143. Reorder List https://youtu.be/l_hy2Vka7VQ
  • 21. Merge Two Sorted Lists https://youtu.be/BxL-Au9ewi8
  • 206. Reverse Linked List https://youtu.be/TvTPj4fmygk
  • 4. Median of Two Sorted Arrays https://youtu.be/X5pWOk9srAE
  • 981. Time Based Key-Value Store https://youtu.be/jD4fNArs5sk
  • 153. Find Minimum in Rotated Sorted Array https://youtu.be/Qm1TiTS0jAE
  • 33. Search in Rotated Sorted Array https://youtu.be/EGTXZEwgJNU
  • 875. Koko Eating Bananas https://youtu.be/QZRI3b8iZpY
  • 74. Search a 2D Matrix https://youtu.be/vKIkPCCbf-k
  • 704. Binary Search https://youtu.be/o0vMa2GFmjE0vMa2GFmjE

Stack

  • 84. Largest Rectangle in Histogram https://youtu.be/Kx2IJw7wRQs
  • 853. Car Fleet https://youtu.be/h7FpmMGK9aQ
  • 739. Daily Temperatures https://youtu.be/cRm6eSnMXkc
  • 22. Generate Parentheses https://youtu.be/DGSbZbKP3LE
  • 150. Evaluate Reverse Polish Notation https://youtu.be/m63dkeGuTsU
  • 155. Min Stack https://youtu.be/iEmoGbyf-C4
  • 20. Valid Parentheses https://youtu.be/r8_jU1csKJc

Sliding Window

  • 239. Sliding Window Maximum https://youtu.be/LlBtNduIj8I
  • 76. Minimum Window Substring https://youtu.be/ZZFK0uFkN1I
  • 567. Permutation in String https://youtu.be/ZHtOPd-AuG4
  • 424. Longest Repeating Character Replacement https://youtu.be/sx2OihkCXlQ
  • 3. Longest Substring Without Repeating Characters https://youtu.be/yiCE8DbuN_Y
  • 121. Best Time to Buy and Sell Stock https://youtu.be/6J3eET5v9u4

Two Pointers

  • 42. Trapping Rain Water https://youtu.be/To6c-rnDse0
  • 11. Container With Most Water https://youtu.be/5LfWirxMW_4
  • 15. 3Sum https://youtu.be/Nl4saPH8rRc
  • 167. Two Sum II - Input Array Is Sorted https://youtu.be/3igpvo94MRE
  • 125. Valid Palindrome https://youtu.be/ztkQ-cx8jGU

Array & Hashing

  • 128. Longest Consecutive Sequence https://youtu.be/N33cS3b8Jdo
  • 271. Encode and Decode Strings https://youtu.be/0tQL6-mZEoE
  • 36. Valid Sudoku https://youtu.be/zhFtF6xVxm0
  • 238. Product of Array Except Self https://youtu.be/p7tIb4TSvR4
  • 347. Top K Frequent Elements https://youtu.be/E8MF4m5_mqY
  • 49. Group Anagrams https://youtu.be/b7bSVsBfOaY
  • 1. Two Sum https://youtu.be/D_a2HAQIEJU
  • 242. Valid Anagram https://youtu.be/badRYBqx2OY
  • 217. Contains Duplicate https://youtu.be/4jR3HHjNX3o

NeetCode-Blind-75

Arrays & Hashing

  • 217. Contains Duplicate https://youtu.be/pHbA9Wsf70Q
  • 242. Valid Anagram https://youtu.be/vP7vRFLYVac
  • 1. Two Sum https://youtu.be/7FLJeTp6KHw
  • 49. Group Anagrams https://youtu.be/Tkjfj-3hO7s
  • 347. Top K Frequent Elements https://youtu.be/n-DJHtpSwr0
  • 238. Product of Array Except Self https://youtu.be/Z7rv2Bk6k_Q
  • 271. Encode and Decode Strings https://youtu.be/HW5cEDI0J4c
  • 128. Longest Consecutive Sequence https://youtu.be/O3XVEhIPwrI

Two Pointers

  • 125. Valid Palindrome https://youtu.be/SPhaAvHRll8
  • 15. 3Sum https://youtu.be/HZwDDFv_XfM
  • 11. Container With Most Water https://youtu.be/YFA_MoXC7dg

Sliding Window

  • 121. Best Time to Buy and Sell Stock https://youtu.be/VW_73t8qp2k
  • 3. Longest Substring Without Repeating Characters https://youtu.be/jbx1llNXSTo
  • 424. Longest Repeating Character Replacement https://youtu.be/stnJAO7Yp1E
  • 76. Minimum Window Substring https://youtu.be/l1GSRhAIJWU

Stack

  • 20. Valid Parentheses https://youtu.be/0Wwm9v-hQuA

Binary Search

  • 153. Find Minimum in Rotated Sorted Array https://youtu.be/wqDW1VQan28
  • 33. Search in Rotated Sorted Array https://youtu.be/uULPqLY0DbE

Linked List

  • 206. Reverse Linked List https://youtu.be/bBRoUkk9Yvo
  • 21. Merge Two Sorted Lists https://youtu.be/WWa3ofcTZg8
  • 143. Reorder List https://youtu.be/gPHCpesm3H4
  • 19. Remove Nth Node From End of List https://youtu.be/vf9hoZH1Fg0
  • 141. Linked List Cycle https://youtu.be/t40dShmMF7M
  • 23. Merge k Sorted Lists https://youtu.be/Q8_P1wj5JuA

Tree

  • 226. Invert Binary Tree https://youtu.be/A8GNxVF08Io
  • 104. Maximum Depth of Binary Tree https://youtu.be/RjxT1eCBuRE
  • 100. Same Tree https://youtu.be/UcDyc6NdyzQ
  • 572. Subtree of Another Tree https://youtu.be/NSQai9olWlI
  • 235. Lowest Common Ancestor of a Binary Search Tree https://youtu.be/bWJIkU8kyVs
  • 102. Binary Tree Level Order Traversal https://youtu.be/6M7UqesaDTQ
  • 98. Validate Binary Search Tree https://youtu.be/JY-fUfmNfxg
  • 230. Kth Smallest Element in a BST https://youtu.be/wrpY6yElCsI
  • 105. Construct Binary Tree from Preorder and Inorder Traversal https://youtu.be/aAyimkWd_Cc
  • 124. Binary Tree Maximum Path Sum https://youtu.be/CRj5u8xFgug
  • 297. Serialize and Deserialize Binary Tree https://youtu.be/DjGBNsqJlsI

Heap/PriorityQueue

  • 295. Find Median from Data Stream https://youtu.be/B7BO0vdtkQ4

Backtracking

  • 39. Combination Sum https://youtu.be/lsX_jIAVS_Q
  • 79. Word Search https://youtu.be/2g1vGXlUoYM

Trie

  • 208. Implement Trie (Prefix Tree) https://youtu.be/yGXn5xD1n6s
  • 211. Design Add and Search Words Data Structure https://youtu.be/5onz2ZrFZmk
  • 212. Word Search II https://youtu.be/FLWcWSe_XMs

Graphs

  • 200. Number of Islands https://youtu.be/217eGONTzaY
  • 133. Clone Graph https://youtu.be/j-m__EMDKp8
  • 417. Pacific Atlantic Water Flow https://youtu.be/AG18MJAru_w
  • 207. Course Schedule https://youtu.be/TUn2CxDaXks
  • 323. Number of Connected Components in an Undirected Graph https://youtu.be/B1hte_hB-t8
  • 261. Graph Valid Tree https://youtu.be/7ViZM1hyrUo

Advanced Graphs

  • 269. Alien Dictionary https://youtu.be/If2BlmCgO4E

1-D DP

  • 70. Climbing Stairs https://youtu.be/FgBaln225vA
  • 198. House Robber https://youtu.be/1tinkA1TxBY
  • 213. House Robber II https://youtu.be/EWp0jYPry9o
  • 5. Longest Palindromic Substring https://youtu.be/f8-XWwv_ZSs
  • 647. Palindromic Substrings https://youtu.be/l5v1VNXn9CQ
  • 91. Decode Ways https://youtu.be/uqLEHEyZiGs
  • 322. Coin Change https://youtu.be/3Yh_POxjGfM
  • 152. Maximum Product Subarray https://youtu.be/fEb8Jm-Ov0A
  • 139. Word Break https://youtu.be/fEb8Jm-Ov0A
  • 300. Longest Increasing Subsequence https://youtu.be/XAvrVTbL7j8

2-D DP

  • 62. Unique Paths https://youtu.be/28-rAI9tjLs
  • 1143. Longest Common Subsequence https://youtu.be/pst_1UEJx7g

Greedy

  • 53. Maximum Subarray https://youtu.be/VXLu7ACJb60
  • 55. Jump Game https://youtu.be/l1lQZ03eUvM

Intervals

  • 57. Insert Interval https://youtu.be/tA6faod5ooY
  • 56. Merge Intervals https://youtu.be/0vwYTCK5Uco
  • 435. Non-overlapping Intervals https://youtu.be/w8bfWJCT0cw
  • 252. Meeting Rooms https://youtu.be/63Q1dHeLoek
  • 253. Meeting Rooms II https://youtu.be/22z3KNCe6q4

Math & Geometry

  • 48. Rotate Image https://youtu.be/Y59tBb5NYgw
  • 54. Spiral Matrix https://youtu.be/NqQgZWALwJU
  • 73. Set Matrix Zeroes https://youtu.be/Zb_PkpWKFuY

Bit Manipulation

  • 191. Number of 1 Bits https://youtu.be/grB7zwCot20
  • 338. Counting Bits https://youtu.be/VKmMqIkKqvE
  • 190. Reverse Bits https://youtu.be/Zb44FpLRLFw
  • 268. Missing Number https://youtu.be/bNIpapq8a10
  • 371. Sum of Two Integers https://youtu.be/jwM-lRbIK_s

Learning

Binary Search

  • 704 Classical Binary Search https://youtu.be/R5A1ei2YYS8
  • 74 Search In Sorted Matrix I https://youtu.be/iXXK4m6vROU
  • 240 Search In Sorted Matrix II https://youtu.be/gNl5u5KnK8Y
  • 34 Find First and Last Position of Element in Sorted Array https://youtu.be/O3rvC_OZqsE
  • 278 First Bad Version https://youtu.be/hf8TW3cL9Is
  • 540 Single Element in a Sorted Array https://youtu.be/pGEEmaIT2dk
  • 374 Guess Number Higher or Lower https://youtu.be/LDuO1_gmIfc
  • 17 Closets In Sorted Array (Lai) https://youtu.be/uSJleagCLV0
  • 15 First Occurrence (Lai) https://youtu.be/LYJx9cFXP8c
  • 16 Last Occurence (Lai) https://youtu.be/UtUswT6mEyk
  • 9 K Closest In Sorted Array (Lai) https://youtu.be/hPAtXySEwYs
  • 658 Find K closest Elements https://youtu.be/9igWYzc4kbo
  • 636 Smallest Element Larger than Target (Lai) https://youtu.be/TOVg4ihSsBY
  • 744 Find Smallest Letter Greater Than Target https://youtu.be/yePIs57DbD0
  • 702 Search in a Sorted Array of Unknown size https://youtu.be/gH02olHHAXs
  • 20 Search In Unknown Sized Sorted Array (Lai) https://youtu.be/UBKuDpw03Qg

Recursion I and Sorting Algorithms

  • 509 Fibonacci Number Lite https://youtu.be/HBWTKRDabcc
  • 50 Pow(x,n) https://youtu.be/aPpRV8cCeVk
  • 4 Selection Sort (Lai) https://youtu.be/w-UeleyZKP4
  • 280 Sort with 2 Stacks https://youtu.be/THB-dtkYFw8
  • Insertion Sort [CLRS]
  • 88 Merge Sorted Array https://youtu.be/fCgzT7CMGMI
  • 912 Sort an Array (Merge Sort) https://youtu.be/XVpbD1lxxjg
  • Merge Two Sorted Linked Lists https://youtu.be/0Q2f8DUBDo4
  • Merge Sort Linked List https://youtu.be/rPbAuMsE95g
  • 10 Quick Sort (Lai) https://youtu.be/6egmBXCFcUU
  • 258 Move 0s To The End I (Lai) https://youtu.be/UyKLWzVaqv4
  • 283 Move Zeors https://youtu.be/bv1LDy59ZLQ
  • 75 Sort Colors = 11 Rainbow Sort (Lai) https://youtu.be/4pmEPe6yMYM

Linked List

  • 206 Reverse Linked List(iterative) = 34 Reverse Linked List (iterative)(Lai) https://youtu.be/vwW7v8l2wRc
  • 206 Reverse linked list(recursive) = 653 Reverse Linked List (recursive)(Lai) https://youtu.be/1SXaCd-_KoA
  • Reverse linked list II (LeetCode)
  • 876 Middle of the Linked List https://youtu.be/BmS2wT2D_hQ
  • 141 Linked List Cycle https://youtu.be/L_D8WoejoMk
  • 39 Insert In Sorted Linked List (Lai) https://youtu.be/WsubCCAUDn0
  • 21 Merge Two Sorted Lists https://youtu.be/0Q2f8DUBDo4
  • Remove Duplicates from Sorted List (LeetCode 83)
  • 189 ReOrder Linked List 练一道得三道 https://youtu.be/6kVw-FndGgw
  • 86 Partition Linked List https://youtu.be/zG5uTRKbDco
  • 148 Sort List https://youtu.be/rPbAuMsE95g
  • 2 Add Two Numbers https://youtu.be/ZRwQl1FKZtA
  • 234 Palindrome Linked List https://youtu.be/trrc8nUR69U
  • 414 Remove Linked List Elements (Lai) https://youtu.be/C7uSvEBvQ70

Queue & Stack

  • 280 Sort with 2 Stacks (Lai) https://youtu.be/THB-dtkYFw8
  • 232. Implement Queue using Stacks https://youtu.be/YiLiZ5nqUB8
  • 155 Min Stack https://youtu.be/rPAtAMG_RUQ
  • 225. Implement Stack using Queues https://youtu.be/N66uH91G-7o
  • 645 Deque By Three Stacks https://youtu.be/ZGUGS5CqNSI
  • 146. LRU Cache
  • 622. Design Circular Queue
  • 641. Design Circular Deque

Binary Tree & Binary Search Tree

  • 144 Binary Tree Preorder Traversal(recursive) https://youtu.be/fGl2pXrR3Uk
  • 94 Binary Tree Inorder Traversal(recursive) https://youtu.be/et8pSZt_YKI
  • 145 Binary Tree PostOrder Traversal(recursive) https://youtu.be/hI1WFNJua38
  • 104 Maximum Depth of Binary Tree https://youtu.be/neAn7bWr7OI
  • 110 Balanced Binary Tree https://youtu.be/p4gSSNo8PXk
  • 101 Symmetric Tree https://youtu.be/vJLxtgfJpP0
  • 100 Same Tree https://youtu.be/bggzFQagRug
  • 951 Flip Equivalent Binary Trees https://youtu.be/wjnX5q7aDfw Time complexity && Space complexity
  • 98 Validate Binary Search Tree https://youtu.be/3CVOiZCMTnc
  • 938 Range Sum of BST https://youtu.be/SXNP3yvOvEk
  • 55 Get Keys In Binary Search Tree In Given Range https://youtu.be/gKEL0to0PYU
  • 700 Search In Binary Search Tree https://youtu.be/0XCGTPJC9CY
  • 701 Insert In Binary Search Tree (recursive) https://youtu.be/F_AmDpDhazo
  • 701 Insert In Binary Search Tree (iterative) https://youtu.be/eHts6A-QXkE
  • 450 Delete Nodes In a BST https://youtu.be/kpacg5Tr3yg
  • 144 Binary Tree Preorder Traversal (iterative) https://youtu.be/-1QnOQ_2pWM
  • 94 Binary Tree Inorder Traversal (iterative) https://youtu.be/ioMBHbqNkaI
  • 145 Binary Tree PostOrder Traversal (iterative) https://youtu.be/d4MnNWYGNEE

Heap and Graph Search I: BFS

  • 215 Kth Largest Element In an Array (minHeap) https://youtu.be/8QQUa1RU0Z8
  • 215 Kth Largest Element In an Array (maxHeap) https://youtu.be/Zy0w7tYDaM4
  • 326 Heapify (Lai) https://youtu.be/UJd8UoAS-EE
  • 363 Heap Offer Operation (Lai) https://youtu.be/Z7whzirlcXg
  • 367Heap Update Operation (Lai) https://youtu.be/CH_Hu31sdys
  • 102 Binary Tree Level Order Traversal https://youtu.be/H1o0mug_aHk
  • 958 Check Completeness of a Binary Tree https://youtu.be/SPRUY-n-qeo
  • Kth Smallest Number In Sorted Matrix https://youtu.be/-9skoB-2ZUI

Graph Search II: DFS

  • 78 Subsets I https://youtu.be/lHSRhbxxi3c
  • 62 All Subsets II (Lai) https://youtu.be/Q5f9UO7DitM
  • 22 Generate Parentheses https://youtu.be/MeCf7f_UIe8
  • 39 Combination Sum https://youtu.be/7H4oTHr7X10
  • 46 Permutations https://youtu.be/jT4e0C7Moew
  • 64 All Permutations I (Lai) https://youtu.be/1L3reMiythI

HashTable and String I

  • 692 Top K Frequent Words https://youtu.be/1NftvCCccLo
  • 347 Top K Frequent Elements
  • 268 Missing Number (HashSet) https://youtu.be/SR5Ayhabj0I
  • 268 Missing Number (Arrat)
  • 349 Intersection of Two Arrays (HashSet) https://youtu.be/hZeOBAVktps
  • 395 Remove Certain Characters(Lai) https://youtu.be/9z3XabUYbIc
  • 1910 Remove All Occurrences of a Substring https://youtu.be/f0PH0i1gmjs
  • 281 Remove Spaces (Lai) https://youtu.be/9ic5Ca1-FPM
  • 58 Length of Last Word https://youtu.be/KixxmOv5c7Y
  • 1047 Remove Adjacent Adjacent Duplicates in String https://youtu.be/mmKYoB-88_8
  • 79 Remove Adjacent Repeated Characters I (Lai) https://youtu.be/P0n9ZYSQjfg
  • 82 Remove Adjacent Repeated Characters IV (Lai) https://youtu.be/FnqpGibUH3E
  • 85 Determine If One String Is Another's Substring (Lai) https://youtu.be/A6DNvsk9Bvs
  • 392 Is Subsequence https://youtu.be/flGU-UMAUC8
  • 706 Design HashMap
  • 219 Contains Duplicate II

String II

  • 76 All Unique Characters I (Lai) https://youtu.be/DJIQoKqAZD4
  • 77 All Unique Characters II (Lai) https://youtu.be/9ZtN2Vr0x84
  • 387 First Unique Character in a String https://youtu.be/cIg79jV0nCE
  • 28 Find the Index of the First Occurrence in a String (Brute Force O(n^2) https://youtu.be/vnARlMx7tR8
  • 8 String to Integer (atoi) https://youtu.be/wxx9YkWzem8
  • 65 Valid Number https://youtu.be/_axf3P7CcNs
  • 344 Reverse String (iterative) https://youtu.be/qTMOYugsPyA
  • 344 Reverse String (recursive) https://youtu.be/cLugiPGHVFE
  • 151 Reverse Words in a String https://youtu.be/AT2KuJo91c0
  • 796 Rotate String https://youtu.be/sFELqdLTSYU
  • 397 Right Shift By N Characters Lai https://youtu.be/aYQkwkj6mTw
  • 848 Shifting Letters https://youtu.be/Ol74Wwva_fw
  • 649 String Replace (basic)(Lai) (StringBuilder) https://youtu.be/wI5qbs72MlA
  • 649 String Replace (Lai) (In-place)
  • 833 Find And Replace in String https://youtu.be/sQ1m0IuQToQ
  • 1528 Shuffle String https://youtu.be/Xq8mdXnqwAQ
  • 408 Valid Word Abbreviation https://youtu.be/1AQmbIQz4-Q
  • 709 To Lower Case https://youtu.be/aqamjh8b_RY
  • 172 String Replace (Lai)
  • 611 Compress String II (Lai)
  • 443 String Compression https://youtu.be/9AeNgq2rjLI
  • 175 Decompress String II (Lai)
  • 394 Decode String
  • 3 Longest Substring Without Repeating Characters https://youtu.be/Lng7QzCTj6s
  • 438 All Anagrams
  • 1493 Longest Subarray of 1's After Deleting One Element
  • 2042 Check if Numbers Are Ascending in a Sentence

Recursion II

  • 51 N Queens https://youtu.be/eDLW6GrFweQ
  • 52 N Queens II https://youtu.be/2x7RZ2l2gAQ
  • 24 Swap Nodes in Pairs https://youtu.be/kb4bpxwzjjs
  • 156 Binary Tree Upside Down https://youtu.be/qVrxgBvMDRk
  • 404 Sum of Left Leaves https://youtu.be/UG4tPK5IpsY
  • 1026 Maximum Difference Between Node and Ancestor https://youtu.be/7k9CBU8Zdrg
  • 235 Lowest Common Ancestor of a Binary Search Tree https://youtu.be/jGX564F7afE
  • 236 Lowest Common Ancestor of a Binary Tree https://youtu.be/bzQYAjPlx7Q
  • 1644 Lowest Common Ancestor of a Binary Tree II https://youtu.be/xmeJCBaHsSI
  • 1650 Lowest Common Ancestor of a Binary Tree III https://youtu.be/eLyGef62s_k
  • 1676 Lowest Common Ancestor of a Binary Tree IV https://youtu.be/bhzv7681IO4
  • 112 Path Sum https://youtu.be/ltLIM0iq4LA
  • 124 Binary Tree Maximum Path Sum https://youtu.be/58KqNi-ySPo

Dynamic Programming I

  • 509 Fibonacci Number https://youtu.be/JzxPldT6-70
  • 674 Longest Continuous Increasing Subsequence https://youtu.be/AMujdJoyCz4
  • 343 Integer Break https://youtu.be/XlV_ZM5HXMc
  • 139 Word Break https://youtu.be/yN52PvtN_6c
  • 55 Jump Game https://youtu.be/dDhsUmX2lGE

Dynamic Programming II

  • 45 Jump Game II https://youtu.be/DU8ggbFRdCw
  • 53 Maximum Subarray https://youtu.be/56BW9WWZI24
  • 72 Edit Distance https://youtu.be/KLQ0xcZc6zE
  • 221 Maximal Square https://youtu.be/VfT-Rsp0b7E
  • 300 Longest Increasing Subsequence https://youtu.be/2N7VQ-H3c7k

Dynamic Programming III

  • 485 Max Consecutive Ones https://youtu.be/qfRN-Spd-WU
  • 487 Max Consecutive Ones II
  • 1004 Max Consecutive Ones III
  • 764 Largest Plus Sign https://youtu.be/54c8E43CRpE
  • 1139 Largest 1-Bordered Square https://youtu.be/n_wjPVSmyEI
  • 105 Largest X Of 1s (Lai) https://youtu.be/Zum9O6CB-Mc
  • 198 House Robber https://youtu.be/X_cDO6EdNd8
  • 638 Largest Square Of Matches (Lai) https://youtu.be/4g2vO85o3Jo
  • Largest SubMatrix Sum Solution 0 https://youtu.be/fmSzWd11e98
  • Solution 1 https://youtu.be/95iI7nGWiJo
  • Solution 2 https://youtu.be/cDAyR_lZ2YU
  • Solution 3 https://youtu.be/F53fDebL6yk

Dynamic Programming IV

  • 152 Maximum Product Subarray https://youtu.be/Ijsi1wBTwlM
  • 300 Longest Increasing Subsequence https://youtu.be/V35DzQh6noA
  • 673 Number of Longest Increasing Subsequence https://youtu.be/FJwFszXPN24
  • 674 Longest Continuous Increasing Subsequence https://youtu.be/VSYH07-qdaM
  • 86 Longest Ascending SubArray (Lai) https://youtu.be/vsI0-_efxO0
  • 683 Count Ascending Subsequence (Lai) https://youtu.be/b0IKJ8uBSEg
  • 744 Find Smallest Letter Greater Than Target https://youtu.be/kGs32rS1AJ4
  • 636 Smallest Element Larger than Target (Lai) https://youtu.be/PsOUkJ6e7pc
  • 217 Largest Set Of Points With Positive Slope (Lai) https://youtu.be/gl4G49m0Hro
  • 343 Integer Break https://youtu.be/z1ndlVPPCfc
  • 87 Max Product Of Cutting Rope (Lai) https://youtu.be/igSBE5Zf7mY
  • 72 Edit Distance https://youtu.be/O8J2qMZIlgY
  • 100 Edit Distance (Lai) https://youtu.be/HeiOSHutlwA
  • 176 Longest Common Substring (Lai) https://youtu.be/fNzHSEUuAdw
  • 1143 Longest Common Subsequence https://youtu.be/rH0VeNN0DK8
  • 177 Longest Common Subsequence (Lai) https://youtu.be/rgx3KUorjN8
  • 2312 Selling Pieces of Wood https://youtu.be/T4EJqM5xMxs
  • 137 Cutting Wood I (Lai) https://youtu.be/o-dhf3ZQHHE
  • 131 Palindrome Partitioning https://youtu.be/LqE-vn2Lnlk
  • 132 Palindrome Partitioning II https://youtu.be/nZiu7zbpe88
  • 143 Minimum Cuts For Palindromes (Lai) https://youtu.be/G2aPOR6MWbY
  • 464 Can I Win https://youtu.be/ATbQnI7ycY8
  • 375 Guess Number Higher or Lower II https://youtu.be/THXy12oH85M
  • 657 Can I Win II (Lai) https://youtu.be/aXDSAyn5thE

DFS II

  • 78 Subsets https://youtu.be/cD24ImQy-gE
  • 416 Partition Equal Subset Sum https://youtu.be/DkVw5uCaRng?feature=shared
  • 63 All Subsets II (Lai) https://youtu.be/RSTuk4N5v_0
  • 90 Subsets II https://youtu.be/f0pqM8w6JaA?feature=shared
  • 77 Combinations https://youtu.be/2T9_CvItk-w
  • 640 All Subsets of Size K (Lai) https://youtu.be/QicgLqBD0kw?feature=shared
  • All Subsets II of Size K (Lai) https://youtu.be/_W7hcKuVUJY
  • 20 Valid Parentheses https://youtu.be/16ATJo_8PG8?feature=shared
  • 22 Generate Parentheses https://youtu.be/17h7tV5s3-0?feature=shared
  • 678 Valid Parenthesis String https://youtu.be/H6yKQaX4Ktw
  • All Valid Permutations Of Parentheses II https://youtu.be/iryA3G3rBLc
  • All Valid Permutations Of Parentheses III https://youtu.be/Uic97MoIh2c
  • 73 Combinations Of Coins (Lai) https://youtu.be/UZCglgFDBnY
  • 254 Factor Combinations https://youtu.be/r-6uuF6HuFo
  • 46 Permutations https://youtu.be/FWtNOVZ_xvk
  • 47 Permutations II https://youtu.be/A7Jy-vaGA6k
  • 643 All Permutations of Subsets (Lai) https://youtu.be/7zncTs71bUI
  • 263 Two Subsets With Min Difference (Lai) https://youtu.be/rxMohHqzrwk
  • 264 Keep Distance For Identical Elements (Lai) https://youtu.be/O6Y4ZSHIcb0

Recursion III

  • 110 Balanced Binary Tree Solution1 https://youtu.be/OJPdH-Kmd_s
  • 110 Balanced Binary Tree Solution2 https://youtu.be/1kzw2_S4xTI
  • 46 Check If Binary Tree Is Balanced (Lai) https://youtu.be/_HpdEe-MRHw
  • 124 Binary Tree Maximum Path Sum https://youtu.be/cACCistj26Y
  • 138 Maximum Path Sum Binary Tree I (Lai) https://youtu.be/wUnXKpyuRP4
  • 144 Binary Tree Preorder Traversal https://youtu.be/I9TfXOeIzik
  • 655 Pre-order Traversal Of Binary Tree (recursive) (Lai) https://youtu.be/jDugE91EwIc
  • 53 Maximum Subarray https://youtu.be/xnz2UzvyCCw
  • 97 Largest SubArray Sum (Lai) https://youtu.be/8FK6jNCqbTM
  • 145 Binary Tree Postorder Traversal https://youtu.be/t5PVHhsflLs
  • 45 Post-order Traversal Of Binary Tree (iterative) (Lai) https://youtu.be/6_pE8WRcLKU
  • 129 Sum Root to Leaf Numbers https://youtu.be/QT2KDrvPiEw
  • 112 Path Sum https://youtu.be/sKqPu4LZ1yY
  • 113 Path Sum II https://youtu.be/4RlfC7R56kw
  • 437 Path Sum III https://youtu.be/M5cyud9xGoE
  • 666 Path Sum IV https://youtu.be/bo6eCZLfSKY
  • 639 Max Path Sum From Leaf To Root (Lai) https://youtu.be/Ipc5zGeSyto
  • 141 Binary Tree Path Sum To Target III (Lai) Solution 1 https://youtu.be/z-p8af6dN9s
  • 141 Binary Tree Path Sum To Target III (Lai) Solution 2 https://youtu.be/27Fl7G4VeLk
  • 140 Maximum Path Sum Binary Tree III (Lai) https://youtu.be/Pl72NASr2hs
  • 114 Flatten Binary Tree to Linked List https://youtu.be/jddZuMCXgeg
  • 523 Flatten Binary Tree to Linked List (Lai) https://youtu.be/nmFlAU5z0SI
  • 105 Construct Binary Tree from Preorder and Inorder Traversal https://youtu.be/Q9PSkmCgRDs
  • 106 Construct Binary Tree from Inorder and Postorder Traversal https://youtu.be/f-ZcqY0Wnoo
  • 213 Reconstruct Binary Tree With Preorder And Inorder (Lai) https://youtu.be/24Z1ekxfpgk
  • 211 Reconstruct Binary Search Tree With Postorder Traversal (Lai) https://youtu.be/-GFz69EB808
  • 102 Binary Tree Level Order Traversal https://youtu.be/M--egQrbBMY
  • 215 Reconstruct Binary Tree With Levelorder And Inorder (Lai) https://youtu.be/lHKdRubqMos

Graph Search Algorithms III

  • 785 Is Graph Bipartite? https://youtu.be/_6VCEOEo4r8
  • 56 Bipartite (Lai) https://youtu.be/rY6bv7_veAI
  • 958 Check Completeness of a Binary Tree https://youtu.be/AhJQuGhhZ-A
  • 47 Check If Binary Tree Is Completed (Lai) https://youtu.be/KJtWztSZ_sw
  • 378 Kth Smallest Element in a Sorted Matrix https://youtu.be/tOxePOuKj8A
  • 26 Kth Smallest Number In Sorted Matrix (Lai) https://youtu.be/VC-5g2mF5uE
  • 373 Find K Pairs with Smallest Sums https://youtu.be/oQaiw1Bg8vw
  • 27 Kth Smallest Sum In Two Sorted Arrays (Lai) https://youtu.be/56SkY3PixFY
  • 221 Maximal Square https://youtu.be/9l_FgnRUfJ4
  • 473 Matchsticks to Square https://youtu.be/qQvhI3X_WXI
  • 638 Largest Square Of Matches (Lai) https://youtu.be/c2DnXrVtF10
  • 773 Sliding Puzzle https://youtu.be/Gd-rr__HpcI
  • 1307 Verbal Arithmetic Puzzle
  • 681 Seven Puzzle (Lai) https://youtu.be/5Gum5Xt2Hls
  • 127 Word Ladder https://youtu.be/8YQde35ywqg
  • 661 Word Ladder (Lai) https://youtu.be/lDW_ya2C2Vw
  • 126 Word Ladder II https://youtu.be/Wi79QQoiLN8
  • 662 Word Ladder II (Lai) https://youtu.be/Yv1eOOlpWpI
  • 318 Maximum Product of Word Lengths https://youtu.be/r7tUZB2qYCI
  • 191 Largest Product Of Length (Lai) https://youtu.be/rbKLRSHNLJM
  • 786 K-th Smallest Prime Fraction https://youtu.be/KfqBCIlqQWE
  • 193 Kth Smallest With Only 3, 5, 7 As Factors (Lai) https://youtu.be/WE-bPJQlJuc
  • 973 K Closest Points to Origin https://youtu.be/aOl7G2kk9Tc
  • 194 Kth Closest Point To <0,0,0> (Lai) https://youtu.be/hB39KivbAcc
  • 417 Pacific Atlantic Water Flow https://youtu.be/WZFVWHDsnq0
  • 665 Pacific Atlantic Flow (Lai) https://youtu.be/q02xtWsVCHg
  • 207 Course Schedule
  • 210 Course Schedule II
  • 430 Course Schedule II (Lai)
  • 269 Alien Dictionary

Trie

  • 79 Word Search https://youtu.be/U07fnpaDc44
  • 212 Word Search II https://youtu.be/8Cdv_9eufqk
  • 431 Word Search II (Lai) https://youtu.be/KywZ_yf1s1g

Fixed Size Sliding Windows

  • 713 Subarray Product Less Than K https://youtu.be/bpj5FIirBfY
  • 1100 Find K-Length Substrings With No Repeated Characters https://youtu.be/v2Ej0dD66OU
  • 438 Find All Anagrams in a String https://youtu.be/WfuL9r8IFB8
  • 3 Longest Substring Without Repeating Characters https://youtu.be/Zkgg875BCpM

Cross-training I

  • 79 Remove Adjacent Repeated Characters I (Lai) https://youtu.be/6N_Z-8X-bt0
  • 1047 Remove All Adjacent Duplicates In String https://youtu.be/aHtnYGN-xXM
  • 258 Move 0s To The End I https://youtu.be/mvZH_lqnPi8
  • 102 Binary Tree Level Order Traversal https://youtu.be/vo-XVkMZJvI
  • 26 Remove Duplicates from Sorted Array https://youtu.be/Xqnm8LlfD58?feature=shared
  • 80 Remove Duplicates from Sorted Array II https://youtu.be/wc9apOfmU2Y
  • Array Deduplication III https://youtu.be/u3Q_xEhOz2Q
  • 118 Array Deduplication IV (Lai) https://youtu.be/qcPgDetHRKE
  • 283 Move Zeroes https://youtu.be/BwnhjQYL-7I
  • 119 Largest And Smallest (Lai) https://youtu.be/j04yk8bdbPc
  • 120 Largest And Second Largest (Lai) https://youtu.be/_Phqc4QMejs
  • 135 Closest Number In Binary Search Tree (Lai) https://youtu.be/ZwxdWULKpfM
  • 270 Closest Binary Search Tree Value https://youtu.be/iBd1LP2vCcE
  • 272 Closest Binary Search Tree Value II https://youtu.be/q1iEp28b5g0
  • 236 Lowest Common Ancestor of a Binary Tree https://youtu.be/bX8ppyQd5Lo
  • 1644 Lowest Common Ancestor of a Binary Tree II https://youtu.be/Tsu8gMWw8Sw
  • 1650 Lowest Common Ancestor of a Binary Tree III https://youtu.be/E7qGpmI1uMI
  • 1676 Lowest Common Ancestor of a Binary Tree IV https://youtu.be/9UZqY44BCjY
  • 126 Lowest Common Ancestor I (Lai) (Similar 236) https://youtu.be/9Ks3T3dxM1M
  • 127 Lowest Common Ancestor II (Lai) https://youtu.be/CYD05dIf3nU
  • 128 Lowest Common Ancestor III (Lai) https://youtu.be/iAClHhFGSBI
  • 129 Lowest Common Ancestor IV (Lai) https://youtu.be/qu44vWb3lEU
  • 647 Lowest Common Ancestor V (Lai) https://youtu.be/aRwkO0yWMZ0
  • 648 Lowest Common Ancestor VI (Lai) https://youtu.be/3CoJWSfg9HA

Review & Strengthen

  • 56 Bipartite (Lai) https://youtu.be/yA4WL_E0En0
  • 785 Is Graph Bipartite? https://youtu.be/R3XFyknyRjU
  • 121 Spiral Order Traverse I (Lai) https://youtu.be/aTYyfTUgKqw
  • 54 Spiral Matrix https://youtu.be/2Elm2uxapX0
  • 59 Spiral Matrix II https://youtu.be/DGwTQop4Z8o
  • 885 Spiral Matrix III https://youtu.be/Mds70zFrGX0
  • 2326 Spiral Matrix IV https://youtu.be/5QcCC8FdWwk
  • 125 Rotate Matrix (Lai) https://youtu.be/AgvP-RfLeAw
  • 48 Rotate Image Solution 1 https://youtu.be/q_QMq6ATe8Y
  • 48 Rotate Image Solution 2 https://youtu.be/YwtmqzPP54k
  • 1528 Shuffle String https://youtu.be/reUGkuMYl9s
  • 197 ReOrder Array (Lai) https://youtu.be/0AIHg5zM5LY
  • 1569 Number of Ways to Reorder Array to Get Same BST
  • 2149 Rearrange Array Elements by Sign
  • 46 Permutations https://youtu.be/kaV9mOjigLY
  • 65 All Permutations II (Lai) https://youtu.be/5QVo2eVIdVY
  • 47 Permutations II https://youtu.be/JfTJuko0luw

Cross-training II

  • 206 Reverse Linked List https://youtu.be/esclzKEbM2E
  • 34 Reverse Linked List (iterative) (Lai) https://youtu.be/1xH3JFYvXxg
  • 450 Delete Node in a BST https://youtu.be/6UqO_wcKyvM
  • 53 Delete In Binary Search Tree (Lai) https://youtu.be/YibO4Jtpon8
  • 700 Search in a Binary Search Tree https://youtu.be/llaNM-0Olj4
  • 52 Search In Binary Search Tree (Lai) https://youtu.be/5MSdpJj38h4
  • 912 Sort an Array (Merge Sort) https://youtu.be/YsqelxkuonU
  • 9 Merge Sort (Lai) https://youtu.be/Zc1O6FHA73g
  • 912 Sort an Array (Quick Sort) https://youtu.be/1ZNQctJ5Vew
  • 10 Quick Sort (Lai) https://youtu.be/bpbc9PVevKk
  • 138 Copy List with Random Pointer https://youtu.be/D7nyu89mFW8
  • 131 Deep Copy Linked List With Random Pointer (Lai) https://youtu.be/xw5cT0qN190
  • 133 Clone Graph https://youtu.be/PGlrfy7_zA0
  • 132 Deep Copy Undirected Graph (Lai) https://youtu.be/Xtt_OKZRPW4
  • 270 Closest Binary Search Tree Value https://youtu.be/ayRxL8n1Dsk
  • 135 Closest Number In Binary Search Tree (Lai) https://youtu.be/MiP5bPgvV08
  • 230 Kth Smallest Element in a BST https://youtu.be/2JN99FqQhOw
  • 136 Largest Number Smaller In Binary Search Tree (Lai) https://youtu.be/72gUHupcOok
  • 1 Two Sum https://youtu.be/PhrV14iig34
  • 1 Two Sum (Map) https://youtu.be/cYgDPyG-ZXI
  • 180 Two Sum (Lai)https://youtu.be/wcCsPMroGk4
  • 180 Two Sum (Set) (Lai) https://youtu.be/4X1IOr2k-bk
  • 181 2 Sum All Pair I (Lai) https://youtu.be/t9VC0Ym4ElQ
  • 182 2 Sum All Pair II (Lai) https://youtu.be/g0IZs2jvr0I
  • 15 3Sum https://youtu.be/jmI3iAywDE4
  • 186 3 Sum (Lai) https://youtu.be/X9OOsZMklDY
  • 18 4Sum https://youtu.be/Vhe_jR57NiA
  • 188 4 Sum (Lai) https://youtu.be/0WWazBVTnSE
  • 167 Two Sum II - Input Array Is Sorted https://youtu.be/FHUEngnWFGY
  • 170 Two Sum III - Data structure design https://youtu.be/CvM3BN1eR9c
  • 560 Subarray Sum Equals K https://youtu.be/RavoWauu1FI
  • 653 Two Sum IV - Input is a BST https://youtu.be/Jt1OnThPw3Y
  • 1099 Two Sum Less Than K https://youtu.be/jUvSCELuLpA
  • 1679 Max Number of K-Sum Pairs https://youtu.be/v9tl8diU0ws
  • 1711 Count Good Meals https://youtu.be/IvC7Khbnxhc
  • 2006 Count Number of Pairs With Absolute Difference K https://youtu.be/PrqzTSuq12Y

Cross-training III

  • 21 Merge Two Sorted Lists https://youtu.be/rMKJRyCJv-Q
  • 40 Merge Two Sorted Linked Lists (Lai) https://youtu.be/v7S_Oozx6pI
  • 133 Merge K Sorted Array (Lai) https://youtu.be/4I8qPAri9w0
  • 23 Merge k Sorted Lists https://youtu.be/rD2wPhoZP0s
  • 134 Merge K Sorted Lists (Lai) https://youtu.be/8G5gjIu_cUI
  • 171 Common Elements In Three Sorted Array (Lai) https://youtu.be/qRGYMoQKLXE
  • 644 Common Elements In K Sorted Lists (Lai) https://youtu.be/ULsJxgJ4BuU
  • 2956 Find Common Elements Between Two Arrays https://youtu.be/VRjJZ0P8x_s
  • 349 Intersection of Two Arrays https://youtu.be/yYLhyEiPdMo
  • 650 Common Numbers Of Two Arrays I(Array version) (Lai) https://youtu.be/_cZZ_8eISDA
  • 651 Common Numbers Of Two Arrays II(Array version) (Lai) https://youtu.be/f028JHZcTDY
  • 652 Common Numbers Of Two Sorted Arrays(Array version) (Lai) https://youtu.be/F1LcKnjyv6s
  • 1047 Remove All Adjacent Duplicates In String https://youtu.be/c3su2aPHYpE
  • 82 Remove Adjacent Repeated Characters IV (Lai) https://youtu.be/1-CSZNJtqC8
  • 485 Max Consecutive Ones https://youtu.be/BSNKyLNK_rI
  • 103 Longest Consecutive 1s (Lai) https://youtu.be/T9dJeRCFPAk
  • 692 Top K Frequent Words https://youtu.be/Qz8GHCsRB70
  • 67 Top K Frequent Words (Lai) https://youtu.be/1JCLUOdemQ0
  • 42 Trapping Rain Water https://youtu.be/s7Gt3Uju450
  • 407 Trapping Rain Water II https://youtu.be/3ZvSCBQXaWc
  • 199 Max Water Trapped I (Lai) https://youtu.be/h4XMCzc2Wrk
  • 200 Max Water Trapped II (Lai) https://youtu.be/JjStuKHInO8
  • 149 Max Points on a Line https://youtu.be/9kL-6QquPHI
  • 216 Most Points On A Line (Lai) https://youtu.be/m-kXYV0o68U

Cross-training IV

  • 102 Binary Tree Level Order Traversal https://youtu.be/holLc1Pe1mY
  • 103 Binary Tree Zigzag Level Order Traversal https://youtu.be/JxFwJsArOFk
  • 704 Binary Search https://youtu.be/uOA1Y6kP9Zo
  • 14 Classical Binary Search (Lai) https://youtu.be/SpEjsK7DozU
  • 374 Guess Number Higher or Lower https://youtu.be/7TVcGEdBgBw
  • 215 Kth Largest Element in an Array https://youtu.be/e9J0Q6Qxx8c
  • 25 K Smallest In Unsorted Array (Lai) https://youtu.be/hs0WqBhmYxk
  • 438 Find All Anagrams in a String https://youtu.be/oWQrnOkhEMM
  • 49 Group Anagrams https://youtu.be/XcbzeJLGNgg
  • 398 All Anagrams (Lai) https://youtu.be/wy4lEJeCwIc
  • 203 Remove Linked List Elements https://youtu.be/_cO8bby1gIQ
  • 414 Remove Linked List Elements (Lai) https://youtu.be/62ohd_23WvA
  • 268 Missing Number https://youtu.be/u2QNyIpcSLQ
  • 68 Missing Number I (Lai) https://youtu.be/vT5u_QqMAvI
  • 146 LRU Cache https://youtu.be/bnZz8uy323E
  • 205 Implement LRU Cache (Lai) https://youtu.be/nw5vBWXiCfw
  • 169 Majority Element https://youtu.be/OsoaWxD7lGE
  • 229 Majority Element II https://youtu.be/B2SNgSVBLkY
  • 206 Majority Number I (Lai) https://youtu.be/QIqaIVSJBVo
  • 378 Kth Smallest Element in a Sorted Matrix https://youtu.be/TVJXUF_P1PI
  • 202 Kth Smallest In Two Sorted Arrays (Lai) https://youtu.be/MJXWkV4VzKA
  • 387 First Unique Character in a String https://youtu.be/Zq5ygAYkYLc
  • 288 First Non-Repeating Character In Stream (Lai) https://youtu.be/UOo0-C7mi0o
  • 560 Subarray Sum Equals K https://youtu.be/a8AO-Q7EMIs

Cross-training V

  • 84 Largest Rectangle in Histogram https://youtu.be/6_1eiF8jszM
  • 198 Largest Rectangle In Histogram (Lai) https://youtu.be/nPKT2vzuJGg
  • 239 Sliding Window Maximum https://youtu.be/_FNYBdnhEus
  • 204 Maximum Values Of Size K Sliding Windows (Lai) https://youtu.be/3lAhdzurQC4
  • 300 Longest Increasing Subsequence https://youtu.be/Mea7gUlAQ2M
  • 1 Longest Ascending Subsequence (Lai) https://youtu.be/9OQVdtFFWQg
  • 85 Maximal Rectangle https://youtu.be/dBBkaKsfawI
  • 102 Largest Rectangle Of 1s (Lai) https://youtu.be/NVNtBamaBdo
  • 496 Next Greater Element I https://youtu.be/RdScbyXfkm0
  • 503 Next Greater Element II https://youtu.be/VSas0XBPTuc
  • 556 Next Greater Element III https://youtu.be/C5y-E4jJQpE
  • 678 Next Greater Number I(optional) (Lai) https://youtu.be/ouhgmLcPK9c
  • 315 Count of Smaller Numbers After Self https://youtu.be/bX36G_P83W4
  • 2148 Count Elements With Strictly Smaller and Greater Elements https://youtu.be/vMuL4dU6W2A
  • 276 Get Count Array (Lai) https://youtu.be/NeqgKgHvdwo