171. Excel Sheet Column Number
Description
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:
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"]
.
Solutions
Solution 1: Base Conversion
The column name in Excel is a representation in base 26. For example, "AB" represents the column number $1 \times 26 + 2 = 28$.
Therefore, we can iterate through the string columnTitle
, convert each character to its corresponding value, and then calculate the result.
The time complexity is $O(n)$, where $n$ is the length of the string columnTitle
. The space complexity is $O(1)$.
1 2 3 4 5 6 |
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1 2 3 4 5 6 7 8 9 |
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1 2 3 4 5 6 7 8 9 10 |
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1 2 3 4 5 6 |
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1 2 3 4 5 6 7 |
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1 2 3 4 5 6 7 8 9 |
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