leetcode-350- 两个数组的交集 II

package com.example.demo;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Test350 {

    /**
     * 双指针，先对数据进行排序预处理，然后使用两个指针分别找到两个数组中相同的值，并放到list中
     */
    public int[] intersect(int[] nums1, int[] nums2) {
        if (nums1 == null || nums1.length == 0 || nums2 == null || nums2.length == 0) {
            return new int[0];
        }
        List<Integer> list = new ArrayList<>();
        Arrays.sort(nums1);
        Arrays.sort(nums2);
        int pointer1 = 0;
        int pointer2 = 0;
        while (pointer1 < nums1.length && pointer2 < nums2.length) {
            if (nums1[pointer1] < nums2[pointer2]) {
                pointer1++;
            } else if (nums1[pointer1] > nums2[pointer2]) {
                pointer2++;
            } else {
                list.add(nums1[pointer1]);
                pointer1++;
                pointer2++;
            }
        }
        int[] res = new int[list.size()];
        for (int i = 0; i < list.size(); i++) {
            res[i] = list.get(i);
        }
        return res;
    }

    public static void main(String[] args) {
        Test350 t = new Test350();
        int[] arr1 = {4, 9, 5};
        int[] arr2 = {9, 4, 9, 8, 4};
        int[] intersect = t.intersect(arr2, arr1);
        for (int i : intersect) {
            System.out.print(i + " ");
        }
    }
}