Longest Uncommon Subsequence I — LeetCode 521 Python Solution

The problem

Given two strings a and b, return the length of the longest uncommon subsequence between a and b. If no such uncommon subsequence exists, return -1.

Example

Input

a = "aba", b = "cdc"

Output

3

Explanation

One longest uncommon subsequence is "aba" because "aba" is a subsequence of "aba" but not "cdc".

Python solution

class Solution:
    def findLUSlength(self, a: str, b: str) -> int:
        return -1 if a == b else max(len(a), len(b))

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 521. Longest Uncommon Subsequence I 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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