171. Excel Sheet Column Number (Easy)
https://leetcode.com/problems/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
Solutions
class Solution {
public int titleToNumber(String s) {
if (s == null || s.isEmpty()) {
return 0;
}
int rank = 1;
int sum = 0;
int multitude = 26;
for (int i = s.length() - 1; i >= 0; i--) {
sum += rank * (s.charAt(i) - 'A' + 1);
rank *= multitude;
}
return sum;
}
}