2215 Find the Difference of Two Arrays - Easy

Problem:

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

answer[0] is a list of all distinct integers in nums1 which are not present in nums2.
answer[1] 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[1] = 2 is present at index 0 of nums2, whereas nums1[0] = 1 and nums1[2] = 3 are not present in nums2. Therefore, answer[0] = [1,3]. For nums2, nums2[0] = 2 is present at index 1 of nums1, whereas nums2[1] = 4 and nums2[2] = 6 are not present in nums2. Therefore, answer[1] = [4,6].

Example 2:

Input: nums1 = [1,2,3,3], nums2 = [1,1,2,2] Output: [[3],[]] Explanation: For nums1, nums1[2] and nums1[3] are not present in nums2. Since nums1[2] == nums1[3], their value is only included once and answer[0] = [3]. Every integer in nums2 is present in nums1. Therefore, answer[1] = [].

Constraints:

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

Problem Analysis:

High-Level Strategy:
- The solution aims to find the differences between two lists, nums1 and nums2.
- It starts by converting both lists into sets using the set() function.
- Then, it uses the difference() method of sets to find elements that are in nums1 but not in nums2 (stored in x), and elements that are in nums2 but not in nums1 (stored in y).
- Finally, it returns a list containing these two sets x and y.
Complexity:
- Converting nums1 and nums2 into sets takes O(n) and O(m) time complexity respectively, where n and m are the sizes of nums1 and nums2.
- Finding the differences between sets using the difference() method takes O(min(len(nums1), len(nums2))) time complexity.
- Therefore, the overall time complexity of this solution is O(n + m).
- The space complexity is O(n + m) as well, due to the space required to store the sets x and y.

Solutions:

class Solution:
    def findDifference(self, nums1: List[int], nums2: List[int]) -> List[List[int]]:
        x = set(nums1).difference(set(nums2))
        y = set(nums2).difference(set(nums1))
        return [x, y]

Walter Teng.

2215 Find the Difference of Two Arrays - Easy

Problem:

Problem Analysis:

Solutions:

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