Is Find Subarrays With Equal Sum easy or hard?

Find Subarrays With Equal Sum is categorized as an Easy problem. The main idea is recognizing that only adjacent pair sums matter and using a hash set to detect duplicates efficiently.

Find Subarrays With Equal Sum Python/Java solution

In Python, use a set to store pair sums while iterating through the array. In Java or C++, use HashSet or unordered_set respectively. The logic is identical: compute nums[i] + nums[i+1], check if it exists in the set, and insert it if not.

How to solve Find Subarrays With Equal Sum in O(n)?

Compute the sum of every adjacent pair while iterating through the array. Maintain a HashSet of previously seen sums. If the current pair sum already exists in the set, two different subarrays must have the same sum, so return true. Otherwise insert the sum and continue.

What is the best approach for Find Subarrays With Equal Sum?

The HashSet approach is the most efficient. Iterate through the array, compute each adjacent pair sum, and store it in a set. If the same sum appears again, two subarrays share the same total. This solution runs in O(n) time with O(n) extra space.

Is Find Subarrays With Equal Sum asked at Google/Amazon/Meta?

Problems involving duplicate detection with hash tables are common in interviews at companies like Amazon, Google, and Meta. While this exact question may vary, the pattern of storing computed values in a set for O(1) lookups appears frequently.

What data structure is used in Find Subarrays With Equal Sum?

A HashSet (or unordered set) is the main data structure in the optimal solution. It stores sums of adjacent pairs so duplicates can be detected in constant average time during a single pass through the array.

What is the time complexity of Find Subarrays With Equal Sum?

The optimal solution runs in O(n) time because the array is scanned once and each pair sum is inserted or checked in a hash set with average O(1) cost. A brute force comparison of all pairs of subarrays takes O(n^2) time.

Description Hints 2 Solution Video 2:20

2395. Find Subarrays With Equal Sum

Easy67.5% acceptance3 companies

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.

Return true if these subarrays exist, and false otherwise.

A subarray is a contiguous non-empty sequence of elements within an array.

Example 1:

Input: nums = [4,2,4]
Output: true
Explanation: The subarrays with elements [4,2] and [2,4] have the same sum of 6.

Example 2:

Input: nums = [1,2,3,4,5]
Output: false
Explanation: No two subarrays of size 2 have the same sum.

Example 3:

Input: nums = [0,0,0]
Output: true
Explanation: The subarrays [nums[0],nums[1]] and [nums[1],nums[2]] have the same sum of 0. 
Note that even though the subarrays have the same content, the two subarrays are considered different because they are in different positions in the original array.

Constraints: