349. Intersection of Two Arrays

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題目敘述

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.

解題思路

Solution

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

class Solution {
    public int[] intersection(int[] nums1, int[] nums2) {
        ArrayList<Integer> result = new ArrayList<>();
        Arrays.sort(nums1);
        Arrays.sort(nums2);
        
        for(int i = 0, j = 0; i < nums1.length && j < nums2.length;) {
            if(nums1[i] == nums2[j]) {
                if(result.size() == 0 || result.get(result.size() - 1) != nums1[i]) {
                    result.add(nums1[i]);
                }
                i++;
                j++;
            } else if(nums1[i] < nums2[j]) {
                i++;
            } else {
                j++;
            }
        }

        return result.stream().mapToInt(i -> i).toArray();
    }
}