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: 1Example 2:
Input: "AB" Output: 28Example 3:
Input: "ZY" Output: 701
Basiclly, it is 26-based, the same as 10-based,
102 = 1 + 1
previous result * 10 + 0 + 1*10+0=10
previous result * 10 +2 + 10*10+2=102
AAA =
1 +
1 * 26 +1
27 * 26 + 1 = 703
/** * @param {string} s * @return {number} */ var titleToNumber = function(s) { if (!s) { return 0; } let sum = 0; let len = s.length; for (let i = 0; i < len; i++) { sum = sum * 26 + (s[i].charCodeAt() - 64); } return sum; };