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Excel Sheet Column Number

Problem statement​

Given a string columnTitle that represents the column title as appear in an Excel sheet, return its corresponding column number.

For example:

A -> 1B -> 2C -> 3...Z -> 26AA -> 27AB -> 28 ...

Example 1:

Input: columnTitle = "A"Output: 1

Example 2:

Input: columnTitle = "AB"Output: 28

Example 3:

Input: columnTitle = "ZY"Output: 701

Constraints:

  • 1 <= columnTitle.length <= 7
  • columnTitle consists only of uppercase English letters.
  • columnTitle is in the range ["A", "FXSHRXW"].

My solution​

/**
 * @param {string} columnTitle
 * @return {number}
 */
var titleToNumber = function(columnTitle) {
    let ans = 0;
    
    for (let i = 0; i < columnTitle.length; i++) {
        // console.log(columnTitle.charCodeAt(i) - "A".charCodeAt(0), "A".charCodeAt(0))
        ans = ans * 26 + columnTitle.charCodeAt(i) - ("A".charCodeAt(0) - 1)
    }
    
    return ans
};