Leetcode 1213 Intersection of Three Sorted Arrays

Problem statement

https://leetcode.com/problems/last-substring-in-lexicographical-order/

Solution

We can just put all arrays to sets and find intersection and then sort answer.

Complexity

It is O(n + m log m), where n is total number of elements and m is number of elements in the smallest array.

Code

class Solution:
    def arraysIntersection(self, A1, A2, A3):
        return sorted(set(A1) & set(A2) & set(A3))

Remark

Or we can use counters to calculate number of times each element is taken and take only those which have frequency 3: time complexity will be O(n).