[leetcode 171] Excel Sheet Column Number

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 ...

Example 1:

Input: "A" Output: 1

Example 2:

Input: "AB" Output: 28

Example 3:

Input: "ZY" Output: 701

 

Constraints:

• 1 <= s.length <= 7
• s consists only of uppercase English letters.
• s is between "A" and "FXSHRXW".

문제 풀이:

난이도 쉬움

26진법 구현하기

class Solution {
public:
    int titleToNumber(string s) {
        
        int len = s.length();
        
        int result = 0;
        if(len == 0){
            return result;
        }
        
        for(int i=0; i<len; i++){
            result *= 26;
            result += s[i] - 64;
        }
        
        return result;
    }
};