Excel Sheet Column Number & Excel Sheet Column Title

1. 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 

 1 class Solution {
 2 public:
 3     int titleToNumber(string s) {
 4         if (s.empty()) return 0;
 5
 6         int result = 0;
 7         for (int i = 0; i < s.size(); i++) {
 8             result = 26 * result + (s[i] - ‘A‘ + 1);
 9         }
10         return result;
11     }
12 };

2. Excel Sheet Column Title

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

For example:

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

 1 class Solution {
 2 public:
 3     string convertToTitle(int n) {
 4         string result;
 5         while (n) {
 6             n--;
 7             int temp = n % 26;
 8             result = (char)(‘A‘ + temp) + result;
 9             n /= 26;
10         }
11         return result;
12     }
13 };