171.excel表列序号.py

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# @lc app=leetcode.cn id=171 lang=python3
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# [171] Excel表列序号
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# https://leetcode-cn.com/problems/excel-sheet-column-number/description/
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# algorithms
# Easy (65.81%)
# Likes:    117
# Dislikes: 0
# Total Accepted:    32.9K
# Total Submissions: 49.4K
# Testcase Example:  '"A"'
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# 给定一个Excel表格中的列名称，返回其相应的列序号。
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# 例如，
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# ⁠   A -> 1
# ⁠   B -> 2
# ⁠   C -> 3
# ⁠   ...
# ⁠   Z -> 26
# ⁠   AA -> 27
# ⁠   AB -> 28
# ⁠   ...
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# 示例 1:
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# 输入: "A"
# 输出: 1
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# 示例 2:
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# 输入: "AB"
# 输出: 28
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# 示例 3:
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# 输入: "ZY"
# 输出: 701
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# 致谢：
# 特别感谢 @ts 添加此问题并创建所有测试用例。
#
#


# @lc code=start
class Solution:

    def titleToNumber(self, s: str) -> int:
        # import string
        # d = {char: num for num, char in enumerate(string.ascii_uppercase, 1)}

        res = 0
        n = len(s)
        for i in range(n):
            # res += 26**(n - 1 - i) * d[s[i]]
            # res = res * 26 + d[s[i]]
            res = res * 26 + ord(s[i]) - 64
        return res


# @lc code=end