[LeetCode 1018] 可被 5 整除的二进制前缀

1018. 可被 5 整除的二进制前缀

二进制的题总是这么神奇

class Solution {
  public:
    vector<bool> prefixesDivBy5(vector<int> &A) {
        int num = 0;
        vector<bool> res;
        for (int i = 0; i < A.size(); i++) {
            num = ((num << 1) + A[i]) % 5;
            if (num == 0 || num == 5)
                res.push_back(true);
            else
                res.push_back(false);
        };
        return res;
    }
};