1529. Minimum Suffix Flips

You are given a 0-indexed binary string target of length n. You have another binary string s of length n that is initially set to all zeros. You want to make s equal to target.

In one operation, you can pick an index i where 0 <= i < n and flip all bits in the inclusive range [i, n - 1]. Flip means changing ‘0’ to ‘1’ and ‘1’ to ‘0’.

Return the minimum number of operations needed to make s equal to target

class Solution {
public:
    int minFlips(string target) {
        int now = 0, res = 0;
        for(auto& ch : target) {
            int v = ch & 0b1111;
            if(now == v) continue;
            res++;
            now = !now;
        }
        return res;
    }
};