LC.P1375[二进制字符串前缀一致的次数]

方法一：维护最大值

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class Solution {
    public int numTimesAllBlue(int[] flips) {
        int ans = 0, max = 0, n = flips.length;
        for (int i = 0; i < n; ++i) {
            max = Math.max(max, flips[i]);
            if (max == i + 1) ++ans;
        }
        return ans;
    }
}
  • 时间复杂度：$O(n)$
  • 空间复杂度：$O(1)$