simply hashmap solution in python


  • 0
    M

    Time: O(n) where n is the length of input string
    Space: O(1)

    class Solution(object):
        def titleToNumber(self, s):
            """
            :type s: str
            :rtype: int
            """
            # time: O(n)
            # space: O(1) - constant
            hashmap = {
                '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
            }
    
            res = 0
            length = len(s)
            for i in range(length):
                res += hashmap[s[i]] * (26 ** (length - 1 - i))
    
            return res
    

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