1375. Number of Times Binary String Is Prefix-Aligned

You have a 1-indexed binary string of length n where all the bits are 0 initially. We will flip all the bits of this binary string (i.e., change them from 0 to 1) one by one. You are given a 1-indexed integer array flips where flips[i] indicates that the bit at index i will be flipped in the ith step.

A binary string is prefix-aligned if, after the ith step, all the bits in the inclusive range [1, i] are ones and all the other bits are zeros.

Return the number of times the binary string is prefix-aligned during the flipping process.

class Solution {
public:
    int numTimesAllBlue(vector<int>& flips) {
        int ma = 0, c = 0, res = 0;
        for(auto& f : flips) {
            ma = max(ma, f);
            c++;
            if(ma == c) res++;
        }
        return res;
    }
};