[LeetCode 171] Excel Sheet Column Number

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Description

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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 1

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• Input: columnTitle = “A”
• Output: 1

Example 2

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• Input: columnTitle = “AB”
• Output: 28

Example 3

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• Input: columnTitle = “ZY”
• Output: 701

Constraints

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

Code

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내 제출

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class Solution {
    public int titleToNumber(String columnTitle) {
        int ans = 0;
        for (int i = 0; i < columnTitle.length(); ++i) {
            ans = ans * 26 + (columnTitle.charAt(i) - 'A' + 1);
        }
        return ans;
    }
}

Runtime	Memory
1 ms	42.3 MB

다른 풀이

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class Solution {
    public int titleToNumber(String columnTitle) {
        int result = 0;
        for (int i = 0; i< columnTitle.length(); i++){
            char c = columnTitle.charAt(i);
            int value = c - 'A' + 1;
            result = result * 26 + value;
        }
        return result;
    }
}

Reference

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• https://github.com/doocs/leetcode/blob/main/solution/0100-0199/0171.Excel%20Sheet%20Column%20Number/Solution.java