# LeetCode 1213. Intersection of Three Sorted Arrays

## Description

https://leetcode.com/problems/intersection-of-three-sorted-arrays/

Given three integer arrays `arr1``arr2` and `arr3` sorted in strictly increasing order, return a sorted array of only the integers that appeared in all three arrays.

Example 1:

```Input: arr1 = [1,2,3,4,5], arr2 = [1,2,5,7,9], arr3 = [1,3,4,5,8]
Output: [1,5]
Explanation: Only 1 and 5 appeared in the three arrays.
```

Example 2:

```Input: arr1 = [197,418,523,876,1356], arr2 = [501,880,1593,1710,1870], arr3 = [521,682,1337,1395,1764]
Output: []
```

Constraints:

• `1 <= arr1.length, arr2.length, arr3.length <= 1000`
• `1 <= arr1[i], arr2[i], arr3[i] <= 2000`

## Explanation

Convert to sets and find intersections.

## Python Solution

``````class Solution:
def arraysIntersection(self, arr1: List[int], arr2: List[int], arr3: List[int]) -> List[int]:

set1 = set(arr1)
set2 = set(arr2)
set3 = set(arr3)

return sorted(set3.intersection(set1, set2))
``````
• Time Complexity: O(NlogN)
• Space Complexity: O(N)