171 Excel Sheet Column Number

Leetcode

Given a string columnTitle that represents the 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: columnTitle = "A"
Output: 1

Example 2:

Input: columnTitle = "AB"
Output: 28

Example 3:

Input: columnTitle = "ZY"
Output: 701

---

public int titleToNumber(String columnTitle) {
    int ret=0;
    int times=1;
    for(int i=columnTitle.length()-1;i>=0;--i){
        ret+=(columnTitle.charAt(i)-'A'+1)*times;
        times*=26;
    }
    return ret;
}