Leetcode Everyday: 349. Intersection of Two Arrays

原创于 2016-05-19 21:48:31 发布 · 234 阅读

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本文介绍了一种计算两个整数数组交集的算法实现。通过使用HashSet存储第一个数组中的元素，然后遍历第二个数组检查元素是否存在，从而找到共同元素。最终返回一个包含唯一交集元素的数组。

https://leetcode.com/problems/intersection-of-two-arrays/

Given two arrays, write a function to compute their intersection.

Example:
Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2].

Note:

Each element in the result must be unique.
The result can be in any order.

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

just find the numbers appear in both arrays.