168.cpp

class Solution {
public:
    string convertToTitle(int n) {
        string result;
        int remain = 0;
        while(n > 0) {
            remain = (--n) % 26;
            result.push_back(remain + 65);
            n /= 26;
        }
        reverse(result.begin(), result.end());
        return result;
    }
};