2025-08-22 18:13:56 +0000 UTC

class Solution:
    def numberOfAlternatingGroups(self, colors: List[int]) -> int:
        res = 0
        if colors[0] != colors[-1] and colors[0] != colors[1]:
            res += 1
        if colors[-1] != colors[-2] and colors[-1] != colors[0]:
            res += 1
        for i in range(1, len(colors) - 1):
            if colors[i] != colors[i - 1] and colors[i] != colors[i + 1]:
                res += 1
        return res