LeetCode 171: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.

//26进制转10进制
class Solution {
public:
int titleToNumber(string s) {
int ret = 0;
for(int i = 0; i < s.size(); i ++)
ret = ret*26 + (s[i]-'A'+1);
return ret;
}
};