excel-sheet-column-title.js

/**
 * Source:  https://leetcode.com/problems/excel-sheet-column-title/
 * Tags:    [Math]
 * Level:   Easy
 * Updated: 2015-04-24
 * Title:   Excel Sheet Column Title
 * Auther:  @imcoddy
 * Content: Given a positive integer, return its corresponding column title as appear in an Excel sheet.
 *
 * For example:
 *
 *     1 -> A
 *     2 -> B
 *     3 -> C
 *     ...
 *     26 -> Z
 *     27 -> AA
 *     28 -> AB
 *
 * Credits:Special thanks to @ifanchu for adding this problem and creating all test cases.
 */

/**
 * @param {number} n
 * @return {string}
 */
var convertToTitle = function(n) {
    var str = 'ZABCDEFGHIJKLMNOPQRSTUVWXYZ';
    var size = 26;
    var result = '';
    while( n > 0 ){
        result = str.charAt(n % size) + result ;
        if (n % size === 0) {
            n = n - size;
        }
        n = Math.floor( n / size );
    }
    console.log(result);
    return result;
};

convertToTitle(25); // X
convertToTitle(26); // Z
convertToTitle(27); // AA
convertToTitle(52); // AA
convertToTitle(26*26); // AA