ExcelSheetColumnNumber [source code]

public class ExcelSheetColumnNumber {
    public int titleToNumber(String s) {
        char[] letters = s.toCharArray();
        int res = 0;
        for (int i = 0; i < letters.length; i++) {
            res = res * 26 + toNumber(letters[i]);
        }
        return res;
    }

    private int toNumber(char letter) {
        if (letter < 'A' || letter > 'Z') return -1;
        return letter - 'A' + 1;
    }
}

比较基础的题目了, 速度是2ms, 51%, 不过 submission 好像没有更好的解了; discussion 也没有更好的解;

Problem Description

Related to question Excel Sheet Column Title

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   

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

Difficulty:Easy
Category:Algorithms
Acceptance:46.66%
Contributor: LeetCode
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Related Topics
math
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Excel Sheet Column Title