## Excel Sheet Column Number

Related to question Excel Sheet Column Title

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28

Credits:

Special thanks to @ts for adding this problem and creating all test cases.

//Can the input be empty? //Can the result overflow 32bits integer? //All the letters are given in capital? class Solution { public: int titleToNumber(string s) { int re = 0; //parse from left to right for(size_t i = 0; i < s.size(); i++){ re = re * 26 + s[i] - 'A' + 1; } return re; } };