171. Excel Sheet Column Number

Problem Statement

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

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

For example:

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

Example:

Input: columnTitle = "A" Output: 1

Input: columnTitle = "AB" Output: 28

Input: columnTitle = "ZY" Output: 701

Solution Approach

The solution splits version strings into individual components, converts them to integers, and performs a straightforward comparison.

Algorithm

1. Splitting: Break version1 and version2 on dots (‘.’).
2. Comparison: Convert components to integers, using 0 for absent values, and compare.
3. Result: Return -1, 1, or 0 based on the comparison outcome.

Implement

    class Solution:
    def titleToNumber(self, columnTitle: str) -> int:
          res = 0
          for c in columnTitle:
              res = res * 26 + ord(c) - 64
          return res 
 

    
    

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