README_EN.md

349. Intersection of Two Arrays

中文文档

Description

Given two integer arrays nums1 and nums2, return an array of their intersection. Each element in the result must be unique and you may return the result in any order.

 

Example 1:

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2]

Example 2:

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [9,4]
Explanation: [4,9] is also accepted.

 

Constraints:

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

Solutions

Python3

class Solution:
    def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
        s = set(nums1)
        res = set()
        for num in nums2:
            if num in s:
                res.add(num)
        return list(res)

Java

class Solution {
    public int[] intersection(int[] nums1, int[] nums2) {
        Set<Integer> s = new HashSet<>();
        for (int num : nums1) {
            s.add(num);
        }
        Set<Integer> t = new HashSet<>();
        for (int num : nums2) {
            if (s.contains(num)) {
                t.add(num);
            }
        }
        int[] res = new int[t.size()];
        int i = 0;
        for (int num : t) {
            res[i++] = num;
        }
        return res;
    }
}

JavaScript

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number[]}
 */
var intersection = function (nums1, nums2) {
    const s = new Set();
    for (const num of nums1) {
        s.add(num);
    }
    let res = new Set();
    for (const num of nums2) {
        if (s.has(num)) {
            res.add(num);
        }
    }
    return [...res];
};

C++

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        unordered_set<int> s;
        for (int num : nums1) s.insert(num);
        unordered_set<int> t;
        vector<int> res;
        for (int num : nums2) {
            if (s.count(num) && !t.count(num)) {
                t.insert(num);
                res.push_back(num);
            }
        }
        return res;
    }
};

Go

func intersection(nums1 []int, nums2 []int) []int {
	s := make(map[int]bool)
	for _, num := range nums1 {
		s[num] = true
	}
	t := make(map[int]bool)
	var res []int
	for _, num := range nums2 {
		if s[num] && !t[num] {
			res = append(res, num)
			t[num] = true
		}
	}
	return res
}

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