Latest Time You Can Obtain After Replacing Characters — C++

// Time:  O(1)
// Space: O(1)

// greedy
class Solution {
public:
    string findLatestTime(string s) {
        if (s[0] == '?') {
            s[0] = s[1] == '?' || s[1] <= '1' ? '1' : '0';
        }
        if (s[1] == '?') {
            s[1] = s[0] == '1' ? '1' : '9';
        }
        if (s[3] == '?') {
            s[3] = '5';
        }
        if (s[4] == '?') {
            s[4] = '9';
        }
        return s;
    }
};