Example with duplicates
Input
nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output
[4, 9]
Common elements are 4 and 9; duplicates are removed and result is sorted.
Full lesson preview
Compute the intersection of two arrays
Return the unique intersection elements of two arrays as a sorted list.
Python practice10 minHashing & SetsBeginnerLast updated March 26, 2026
Problem statement
Given two integer arrays nums1 and nums2, return a sorted list of unique integers that appear in both arrays. The result should contain no duplicates and should be sorted in ascending order. Aim for O(n + m) expected time using hashing/set operations, where n and m are the lengths of the two arrays.
Task
Use sets to deduplicate and compute intersection efficiently, then return the result in sorted order for deterministic output.
Examples
Input format
Two lists of integers: intersection_sorted(nums1, nums2)
Output format
A list of unique integers that appear in both arrays, sorted ascending.
Constraints
0 <= len(nums1), len(nums2) <= 10^5; elements are integers within 32-bit signed range.
Samples
Sample 1
Input
intersection_sorted([1,2,2,1], [2,2])
Output
[2]
2 is the only common element; duplicates removed.