Find Subarrays With Equal Sum — LeetCode 2395 Python Solution

The problem

Given a 0-indexed integer array nums, determine whether there exist two subarrays of length 2 with equal sum. Note that the two subarrays must begin at different indices.

Example

Input

nums = [4,2,4]

Output

true

Explanation

The subarrays with elements [4,2] and [2,4] have the same sum of 6.

Python solution

class Solution:
    def findSubarrays(self, nums: List[int]) -> bool:
        vis = set()
        for a, b in pairwise(nums):
            if (x := a + b) in vis:
                return True
            vis.add(x)
        return False

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 2395. Find Subarrays With Equal Sum is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table.

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

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