Sum of Digits of String After Convert — LeetCode 1945 Python Solution

The problem

You are given a string s consisting of lowercase English letters, and an integer k. Your task is to convert the string into an integer by a special process, and then transform it by summing its digits repeatedly k times.

Python solution

class Solution:
    def getLucky(self, s: str, k: int) -> int:
        s = ''.join(str(ord(c) - ord('a') + 1) for c in s)
        for _ in range(k):
            t = sum(int(c) for c in s)
            s = str(t)
        return int(s)

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1945. Sum of Digits of String After Convert is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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