LeetCode-in-Java
171. Excel Sheet Column Number
Easy
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
Example 4:
Input: columnTitle = “FXSHRXW”
Output: 2147483647
Constraints:
1 <= columnTitle.length <= 7columnTitleconsists only of uppercase English letters.columnTitleis in the range["A", "FXSHRXW"].
Solution
public class Solution {
public int titleToNumber(String s) {
int num = 0;
int pow = 0;
for (int i = s.length() - 1; i >= 0; i--) {
num += (int) Math.pow(26, pow++) * (s.charAt(i) - 'A' + 1);
}
return num;
}
}