171. Excel Sheet Column Number
Easy
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
package leetcode.easy; public class ExcelSheetColumnNumber { @org.junit.Test public void test() { System.out.println(titleToNumber("A")); System.out.println(titleToNumber("AB")); System.out.println(titleToNumber("ZY")); } public int titleToNumber(String s) { int result = 0; int exponent = 0; for (int i = s.length() - 1; i >= 0; i--) { result += (s.charAt(i) - 'A' + 1) * Math.pow(26, exponent); exponent++; } return result; } }