Intersection of Two Arrays II.java

import java.util.Arrays;

class Solution {
    public int[] intersect(int[] nums1, int[] nums2) {
        int[] arr = new int[1001];  // To count frequencies of elements in nums1
        int[] result = new int[1001];  // To store the result

        // Count the frequencies of each number in nums1
        for (int num : nums1) {
            arr[num]++;
        }

        int ctr = 0;  // Counter for the result array
        // Traverse nums2 to find common elements
        for (int num : nums2) {
            if (arr[num] > 0) {
                result[ctr++] = num;
                arr[num]--;
            }
        }

        // Return only the filled portion of the result array
        return Arrays.copyOfRange(result, 0, ctr);
    }
}