Count Pairs Of Similar Strings — LeetCode 2506 Python Solution

The problem

You are given a 0-indexed string array words. Two strings are similar if they consist of the same characters.

Example

Input

words = ["aba","aabb","abcd","bac","aabc"]

Output

2

Explanation

There are 2 pairs that satisfy the conditions:

Python solution

class Solution:
    def similarPairs(self, words: List[str]) -> int:
        ans = 0
        cnt = Counter()
        for s in words:
            x = 0
            for c in map(ord, s):
                x |= 1 << (c - ord("a"))
            ans += cnt[x]
            cnt[x] += 1
        return ans

Complexity

Pattern: Bit Manipulation

Use XOR, masks and the low-bit trick to replace whole data structures with an integer. LeetCode 2506. Count Pairs Of Similar Strings is filed here because LeetCode tags it Bit Manipulation, which is the vocabulary this hub collects.

The bit manipulation guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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