> ## Documentation Index
> Fetch the complete documentation index at: https://leetcode-py.wisl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> leetcode-py is a Python LeetCode practice environment generator with one CLI: lcpy. It is not a service or platform.
> Each problem is a directory under leetcode/ with README.md, solution.py, test_solution.py, helpers.py, and playground.ipynb. lcpy gen creates them from JSON templates bundled with the package.
> Examples are backed by tests; copy them verbatim.

# Find the Difference of Two Arrays

> Tested Python solution for LeetCode 2215 with 16 pytest cases. Generate a practice environment with lcpy.

LeetCode 2215, [Easy](/catalog/easy). Topics: [Array](/catalog/topics/array), [Hash Table](/catalog/topics/hash-table). [View on LeetCode](https://leetcode.com/problems/find-the-difference-of-two-arrays/description/).

Generate this problem as a practice environment: tested reference solution, 16 [parametrized pytest cases](/practice/testing), and a playground notebook:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
lcpy gen -n 2215   # by problem number
lcpy gen -s find_the_difference_of_two_arrays   # by problem name
```

## Problem

Given two **0-indexed** integer arrays `nums1` and `nums2`, return *a list* `answer` *of size* `2` where:

* `answer[0]` is a list of all **distinct** integers in `nums1` which are **not** present in `nums2`.
* `answer[1]` is a list of all **distinct** integers in `nums2` which are **not** present in `nums1`.

**Note** that the integers in the lists may be returned in **any** order.

### Examples

```
Input: nums1 = [1,2,3], nums2 = [2,4,6]
Output: [[1,3],[4,6]]
Explanation: For nums1, nums1[1] = 2 is present at index 0 of nums2, whereas nums1[0] = 1 and nums1[2] = 3 are not present in nums2. Therefore, answer[0] = [1,3]. For nums2, nums2[0] = 2 is present at index 1 of nums1, whereas nums2[1] = 4 and nums2[2] = 6 are not present in nums1. Therefore, answer[1] = [4,6].
```

```
Input: nums1 = [1,2,3,3], nums2 = [1,1,2,2]
Output: [[3],[]]
Explanation: For nums1, nums1[2] and nums1[3] are not present in nums2. Since nums1[2] == nums1[3], their value is only included once and answer[0] = [3]. Every integer in nums2 is present in nums1. Therefore, answer[1] = [].
```

### Constraints

* 1 \<= nums1.length, nums2.length \<= 1000
* -1000 \<= nums1\[i], nums2\[i] \<= 1000

## Solution

Reference implementation from [solution.py on GitHub](https://github.com/wislertt/leetcode-py/blob/main/leetcode/find_the_difference_of_two_arrays/solution.py), full suite in [test\_solution.py](https://github.com/wislertt/leetcode-py/blob/main/leetcode/find_the_difference_of_two_arrays/test_solution.py):

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
class Solution:
    # Time: O(n + m)
    # Space: O(n + m)
    def find_difference(self, nums1: list[int], nums2: list[int]) -> list[list[int]]:
        set1, set2 = set(nums1), set(nums2)
        return [sorted(set1 - set2), sorted(set2 - set1)]
```

## Complexity

| Time | Space |
| - | - |
| O(n + m) | O(n + m) |

## Tags

[NeetCode All](/catalog/neetcode).


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