# 给定一个Excel表格中的列名称，返回其相应的列序号。
# 例如，
#     A -> 1
#     B -> 2
#     C -> 3
#     ...
#     Z -> 26
#     AA -> 27
#     AB -> 28
#     ...
#
# 示例 1:
# 输入: "A"
# 输出: 1
#
# 示例 2:
# 输入: "AB"
# 输出: 28
#
# 示例 3:
# 输入: "ZY"
# 输出: 701


class Solution:
    def titleToNumber(self, s: str) -> int:
        dicts = {'A': 1,
                 'B': 2,
                 'C': 3,
                 'D': 4,
                 'E': 5,
                 'F': 6,
                 'G': 7,
                 'H': 8,
                 'I': 9,
                 'J': 10,
                 'K': 11,
                 'L': 12,
                 'M': 13,
                 'N': 14,
                 'O': 15,
                 'P': 16,
                 'Q': 17,
                 'R': 18,
                 'S': 19,
                 'T': 20,
                 'U': 21,
                 'V': 22,
                 'W': 23,
                 'X': 24,
                 'Y': 25,
                 'Z': 26,
                 }
        lens = len(s)
        sum = 0
        for i in range(lens-1, -1, -1):
            sum += dicts[s[i]] * (26**(lens-1-i))
        return sum