Excel Sheet Column Number · Interview Problem

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Leetcode

Easy

Math

Strings

Excel Sheet Column Number

Convert an Excel-style column label like A, Z, AA, or FXSHRXW into its corresponding column number.

Acceptance 100%

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Problem Statement

Problem

You are given a string columnTitle that represents an Excel column title.

Excel columns are labeled using uppercase letters starting from A:

A = 1
B = 2
...
Z = 26
AA = 27
AB = 28

Your task is to return the numeric column index represented by the title.

Treat the title as a base-26 number where A maps to 1 and Z maps to 26, rather than 0 to 25.

Notes

The input contains only uppercase English letters.
The answer fits in a 32-bit signed integer for standard interview constraints.

Input Format

A single string columnTitle.
columnTitle consists only of uppercase letters A to Z.

Output Format

Return a single integer: the Excel column number for columnTitle.

Constraints

$1 \le |columnTitle|$
columnTitle contains only uppercase letters A-Z
The result fits in a signed 32-bit integer

Examples

Sample cases returned by the problem API.

Example 1

Input

columnTitle = "A"

Output

Explanation

A corresponds to 1.

Example 2

Input

columnTitle = "AB"

Output

Explanation

AB = 1 × 26 + 2 = 28.

Show 1 more example

Example 3

Input

columnTitle = "ZY"

Output

Explanation

ZY = 26 × 26 + 25 = 701.

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