leetcode 171. Excel Sheet Column Number ( Python )

描述

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

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

Input: "A"
Output: 1
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Example 2:

Input: "AB"
Output: 28
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Example 3:

Input: "ZY"
Output: 701
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解析

根據題意，在將字母的二十六進制，轉換爲十進制，比較簡單，時間複雜度爲 O(N)，空間複雜度爲 O(1)。

解答

class Solution(object):
def titleToNumber(self, s):
    """
    :type s: str
    :rtype: int
    """
    result = 0
    count = 0
    for i in s[::-1]:
        result += 26**count*(ord(i)-ord('A')+1)
        count += 1
    return result                     	      
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運行結果

Runtime: 20 ms, faster than 66.42% of Python online submissions for Excel Sheet Column Number.
Memory Usage: 11.7 MB, less than 41.88% of Python online submissions for Excel Sheet Column Number.
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