三个有序数组的交集

/*
 * LeetCode Problem 1213: Intersection of Three Sorted Arrays
 * Given three integer arrays arr1, arr2 and arr3 sorted in strictly increasing order, 
 * return a sorted array of only the integers that appeared in all three arrays.
 * 
 * Approach using Java Streams:
 * 1. Convert each array to a stream.
 * 2. Convert the streams to sets to facilitate intersection operations.
 * 3. Perform intersection of the sets.
 * 4. Collect the result back to a list.
 */

import java.util.*;
import java.util.stream.*;

public class Solution {
    public List<Integer> arraysIntersection(int[] arr1, int[] arr2, int[] arr3) {
        Set<Integer> set1 = Arrays.stream(arr1).boxed().collect(Collectors.toSet());
        Set<Integer> set2 = Arrays.stream(arr2).boxed().collect(Collectors.toSet());
        Set<Integer> set3 = Arrays.stream(arr3).boxed().collect(Collectors.toSet());

        return set1.stream()
                .filter(set2::contains)
                .filter(set3::contains)
                .sorted()
                .collect(Collectors.toList());
    }
}