# Find the Difference of Two Arrays

Category

Hash Map / Set

Checkbox

Checkbox

Difficulty

Easy

Index

20

Key Ideas

The key idea to solve this problem is to use a hash set to efficiently find the difference between two arrays by comparing their elements.

Problem Number

2215

Problem Summary

**Problem Summary:**The problem is about finding the difference between two arrays and returning the result as a new array. The arrays can contain both positive and negative integers, and the order of the elements does not matter.

**Key Pitfalls:**Some key pitfalls to watch out for when solving this problem include handling duplicate elements in the arrays, considering edge cases such as empty arrays or arrays with only one element, and ensuring the time complexity is efficient by using appropriate data structures or algorithms.

Solution Summary

The best solution to find the difference of two arrays is to use a hash set. We can start by adding all the elements from the first array into the set. Then, we iterate through the second array and check if each element exists in the set. If it does, we remove it from the set. After iterating through both arrays, the remaining elements in the set will be the difference between the two arrays. This solution has a time complexity of O(n), where n is the length of the arrays, since adding and removing elements from a hash set is constant time on average.

Tags

Array

Hash Table