Tags: "leetcode", "array", access_time 1-min read

Intersection of Three Sorted Arrays

Created: October 16, 2019 by [lek-tin]

Last updated: October 16, 2019

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.

Constraints:

1. 1 <= arr1.length, arr2.length, arr3.length <= 1000
2. 1 <= arr1[i], arr2[i], arr3[i] <= 2000

Solution

Python

class Solution:
    def arraysIntersection(self, arr1: List[int], arr2: List[int], arr3: List[int]) -> List[int]:
        pos2, pos3 = 0, 0
        res = []
        for target in arr1:
            while pos2 < len(arr2) and arr2[pos2] < target:
                pos2 += 1
            while pos3 < len(arr3) and arr3[pos3] < target:
                pos3 += 1
            if pos2 < len(arr2) and pos3 < len(arr3):
                if arr2[pos2] == arr3[pos3] == target:
                    res.append(target)

        return res