3206. Alternating Groups I
There is a circle of red and blue tiles. You are given an array of integers colors
. The color of tile i
is represented by colors[i]
:
colors[i] == 0
means that tilei
is red.colors[i] == 1
means that tilei
is blue.
Every 3 contiguous tiles in the circle with alternating colors (the middle tile has a different color from its left and right tiles) is called an alternating group.
Return the number of alternating groups.
Note that since colors
represents a circle, the first and the last tiles are considered to be next to each other.
Example 1:
Input: colors = [1,1,1]
Output: 0
Explanation:
Example 2:
Input: colors = [0,1,0,0,1]
Output: 3
Explanation:
Alternating groups:
Constraints:
3 <= colors.length <= 100
0 <= colors[i] <= 1
class Solution {
public int numberOfAlternatingGroups(int[] colors) {
// base case
if (colors.length <= 1){
return 0;
}
int fast = 1;
int slow = colors.length -1;
int cur = 0;
int result = 0;
if (colors[cur] != colors[fast] && colors[cur] != colors[slow]){
result++;
cur++;
fast++;
slow = 0;
}else{
cur++;
fast++;
slow = 0;
}
while(cur < colors.length){
if (colors[cur] != colors[fast] && colors[cur] != colors[slow]){
result++;
}
cur++;
fast++;
slow++;
if (cur == colors.length - 1){
fast = 0;
}
}
return result;
}
}