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
从A到Z依次代表从1到26，按照26进制进位。
代码如下：
1 class Solution { 2 public: 3 int titleToNumber(string s) { 4 int n = s.length(); 5 int m = n; 6 int result = 0; 7 if(n == 0) 8 { 9 return 0; 10 } 11 result = (int)s[m-1]; 12 result -= 64; 13 for(int i = 1; i < n+1; i++) 14 { 15 m--; 16 if(m == 0) 17 { 18 return result; 19 } 20 int p = 1; 21 for(int j = 0; j < i; j++) 22 { 23 p *= 26; 24 } 25 int re = (int)s[m-1]; 26 re -= 64; 27 result = result + re * p; 28 } 29 return result; 30 } 31 };
原文：http://www.cnblogs.com/shellfishsplace/p/6042439.html