[LeetCode][JavaScript]Excel Sheet Column Number

Excel Sheet Column Number

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 

https://leetcode.com/problems/excel-sheet-column-number/

 

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进制转换，比兄弟题简单。

/**
 * @param {string} s
 * @return {number}
 */
var titleToNumber = function(s) {
    var map = [];
    var codeA = "A".charCodeAt(); 
    
    s = s.toUpperCase();
    var power = 0;
    var result = 0;
    for(var i = s.length - 1; i >= 0; i--, power++){
        var ch = s[i];
        result += ( ch.charCodeAt() - codeA + 1 ) * Math.pow(26, power);
    }
    
    return result;
};