Formatted question description: https://leetcode.ca/all/2215.html

# 2215. Find the Difference of Two Arrays (Easy)

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

• answer is a list of all distinct integers in nums1 which are not present in nums2.
• answer 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.

Example 1:

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

Example 2:

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


Constraints:

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

Companies:

Related Topics:
Hash Table

Similar Questions:

## Solution 1. Hash Set

// OJ: https://leetcode.com/problems/find-the-difference-of-two-arrays/
// Time: O(A + B)
// Space: O(A + B)
class Solution {
public:
vector<vector<int>> findDifference(vector<int>& A, vector<int>& B) {
unordered_set<int> sa(begin(A), end(A)), sb(begin(B), end(B));
vector<vector<int>> ans(2);
for (int n : sa) {
if (sb.count(n) == 0) ans.push_back(n);
}
for (int n : sb) {
if (sa.count(n) == 0) ans.push_back(n);
}
return ans;
}
};


## Discuss

https://leetcode.com/problems/find-the-difference-of-two-arrays/discuss/1886960/