問題 https://leetcode-cn.com/problems/excel-sheet-column-number/
練習使用JavaScript解答
/**
* @param {string} s
* @return {number}
*/
var titleToNumber = function(s) {
var i,sum = 0;
for(i=0;i<s.length;++i) {
sum *= 26;
sum += s.charCodeAt(i) - 64;
}
return sum;
};