Daily LeetCode Problems: Problem 2215. Find the Difference of Two Arrays

Introduction

In this article, we will discuss LeetCode problem 2215 “Find the Difference of Two Arrays”. We will look at the problem statement, its constraints, and its approach to solving the problem. We will also discuss the pseudocode, time complexity, and space complexity of our solution.

Problem Statement

The problem statement is as follows:

Given two integer arrays arr1 and arr2, return the difference between the maximum value of arr2 and the minimum value of arr1.

Constraints

• 1 <= arr1.length, arr2.length <= 1000
• -10⁹ <= arr1[i], arr2[i] <= 10⁹

Approach

The solution to this problem is simple. We can use the built-in functions min and max to find the minimum value of arr1 and the maximum value of arr2, respectively. We can then subtract the minimum value of arr1 from the maximum value of arr2 and return the result.

Pseudocode

Here is the pseudocode for our solution:

function findDifference(arr1, arr2):
    min_arr1 = min(arr1)
    max_arr2 = max(arr2)
    return max_arr2 - min_arr1

Time Complexity

The time complexity of our solution is O(n), where n is the length of the larger array between arr1 and arr2. This is because we need to loop through the larger array to find the maximum value of arr2 and the minimum value of arr1.

Space Complexity

The space complexity of our solution is O(1), since we only need to store the minimum value of arr1 and the maximum value of arr2 in two variables.

Complete Solution

Here is the complete solution to the problem:

Python

class Solution:
  def findDifference(self, nums1: List[int], nums2: List[int]) -> List[List[int]]:
    set1 = set(nums1)
    set2 = set(nums2)
    return [set1 - set2, set2 - set1]

C++

class Solution {
 public:
  vector<vector<int>> findDifference(vector<int>& nums1, vector<int>& nums2) {
    vector<vector<int>> ans(2);
    unordered_set<int> set1{begin(nums1), end(nums1)};
    unordered_set<int> set2{begin(nums2), end(nums2)};

    for (const int num : set1)
      if (!set2.count(num))
        ans[0].push_back(num);

    for (const int num : set2)
      if (!set1.count(num))
        ans[1].push_back(num);

    return ans;
  }
};

Java

class Solution {
  public List<List<Integer>> findDifference(int[] nums1, int[] nums2) {
    Set<Integer> set1 = Arrays.stream(nums1).boxed().collect(Collectors.toSet());
    Set<Integer> set2 = Arrays.stream(nums2).boxed().collect(Collectors.toSet());
    Arrays.stream(nums1).forEach(set2::remove);
    Arrays.stream(nums2).forEach(set1::remove);
    return Arrays.asList(new ArrayList<>(set1), new ArrayList<>(set2));
  }
}

Conclusion

In this article, we have discussed LeetCode problem 2215 “Find the Difference of Two Arrays”. We have looked at the problem statement, its constraints, and its approach to solving the problem. We have also discussed the pseudocode, time complexity, and space complexity of our solution. Finally, we have provided the complete solution to the problem in Python, Java and C++.

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