Question

Formatted question description: https://leetcode.ca/all/171.html

 171	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 (26*26+25)

Algorithm

It is equivalent to a problem of converting from hexadecimal to decimal. It is not difficult, as long as the conversion is bit by bit.

Code

Java

public class Excel_Sheet_Column_Number {
    class Solution {
        public int titleToNumber(String s) {
            int result = 0;

            for (int i = 0; i < s.length(); i++) {
                result = result * 26 + (s.charAt(i) - 'A' + 1);
            }

            return result;
        }
    }
}

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