Check If Digits Are Equal in String After Operations I

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Question

Approach

To solve this, I repeatedly reduced the string by replacing it with the sequence formed by taking the sum of each pair of adjacent digits modulo 10. I continued this process until only two digits remained. Then, I simply checked if those final two digits were equal—returning True if they were and False otherwise.

Implementation

class Solution:
    def hasSameDigits(self, s: str) -> bool:
        while len(s) > 2:
            new_s = []
            for i in range(len(s) - 1):
                new_s.append(str((int(s[i]) + int(s[i + 1])) % 10))
            s = "".join(new_s)
        return s[0] == s[1]

Complexities

• Time: O(n^2)
• Space: O(n)