Description
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 nums1. 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
Solutions
Solution 1: Hash Table
We define two hash tables s1 and s2 to store the elements in arrays nums1 and nums2 respectively. Then we traverse each element in s1. If this element is not in s2, we add it to the first list in the answer. Similarly, we traverse each element in s2. If this element is not in s1, we add it to the second list in the answer.
The time complexity is O(n), and the space complexity is O(n). Where n is the length of the array.
PythonJavaC++GoTypeScriptRustJavaScriptPHP
class Solution:
def findDifference(self, nums1: List[int], nums2: List[int]) -> List[List[int]]:
s1, s2 = set(nums1), set(nums2)
return [list(s1 - s2), list(s2 - s1)](code-box)
class Solution {
public List<List<Integer>> findDifference(int[] nums1, int[] nums2) {
Set<Integer> s1 = convert(nums1);
Set<Integer> s2 = convert(nums2);
List<Integer> l1 = new ArrayList<>();
List<Integer> l2 = new ArrayList<>();
for (int v : s1) {
if (!s2.contains(v)) {
l1.add(v);
}
}
for (int v : s2) {
if (!s1.contains(v)) {
l2.add(v);
}
}
return List.of(l1, l2);
}
private Set<Integer> convert(int[] nums) {
Set<Integer> s = new HashSet<>();
for (int v : nums) {
s.add(v);
}
return s;
}
}(code-box)
class Solution {
public:
vector<vector<int>> findDifference(vector<int>& nums1, vector<int>& nums2) {
unordered_set<int> s1(nums1.begin(), nums1.end());
unordered_set<int> s2(nums2.begin(), nums2.end());
vector<vector<int>> ans(2);
for (int v : s1) {
if (!s2.contains(v)) {
ans[0].push_back(v);
}
}
for (int v : s2) {
if (!s1.contains(v)) {
ans[1].push_back(v);
}
}
return ans;
}
};(code-box)
func findDifference(nums1 []int, nums2 []int) [][]int {
s1, s2 := make(map[int]bool), make(map[int]bool)
for _, v := range nums1 {
s1[v] = true
}
for _, v := range nums2 {
s2[v] = true
}
ans := make([][]int, 2)
for v := range s1 {
if !s2[v] {
ans[0] = append(ans[0], v)
}
}
for v := range s2 {
if !s1[v] {
ans[1] = append(ans[1], v)
}
}
return ans
}(code-box)
function findDifference(nums1: number[], nums2: number[]): number[][] {
const s1: Set<number> = new Set(nums1);
const s2: Set<number> = new Set(nums2);
nums1.forEach(num => s2.delete(num));
nums2.forEach(num => s1.delete(num));
return [Array.from(s1), Array.from(s2)];
}(code-box)
use std::collections::HashSet;
impl Solution {
pub fn find_difference(nums1: Vec<i32>, nums2: Vec<i32>) -> Vec<Vec<i32>> {
vec![
nums1
.iter()
.filter_map(|&v| if nums2.contains(&v) { None } else { Some(v) })
.collect::<HashSet<i32>>()
.into_iter()
.collect(),
nums2
.iter()
.filter_map(|&v| if nums1.contains(&v) { None } else { Some(v) })
.collect::<HashSet<i32>>()
.into_iter()
.collect(),
]
}
}(code-box)
/**
* @param {number[]} nums1
* @param {number[]} nums2
* @return {number[][]}
*/
var findDifference = function (nums1, nums2) {
const s1 = new Set(nums1);
const s2 = new Set(nums2);
nums1.forEach(num => s2.delete(num));
nums2.forEach(num => s1.delete(num));
return [Array.from(s1), Array.from(s2)];
};(code-box)
class Solution {
/**
* @param Integer[] $nums1
* @param Integer[] $nums2
* @return Integer[][]
*/
function findDifference($nums1, $nums2) {
$s1 = array_flip($nums1);
$s2 = array_flip($nums2);
$diff1 = array_diff_key($s1, $s2);
$diff2 = array_diff_key($s2, $s1);
return [array_keys($diff1), array_keys($diff2)];
}
}(code-box)
