171. Excel Sheet Column Number.md

#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

AA的第一个A的权值就是26，1*26。其他同理推就好了

Java Solution

public class Solution {
    public int titleToNumber(String s) {
        int Number=0;
        for(int i=0;i<s.length();i++){
            Number += (s.charAt(i)-64)*Math.pow(26,s.length()-1-i);
        }
        return Number;
    }
}

后来又发现我这个...有点蠢

Java Solution(Reference)

public class Solution {
    public int titleToNumber(String s) {
        int Number=0;
        for(int i=0;i<s.length();i++){
            Number *= 26;
            Number += s.charAt(i)-'A'+1;
        }
        return Number;
    }
}