Challenges hashing and tries

#1

sir have a look on my code,one of my test case is getting incorrect

package chall_Hashing_and_trees;
import java.util.*;
public class intersection_of_two_arrays {
static Scanner s=new Scanner(System.in);
public static void main(String[] args) {
// TODO Auto-generated method stub
int n= s.nextInt();
int[] arr1=new int[n];
for(int i=0 ;i<n ;i++) {
arr1[i] =s.nextInt();
}
HashMap<Integer ,Integer> map =new HashMap<>();
for(int i =0 ;i < n;i++) {
if(map.containsKey(arr1[i])) {
int ov=map.get(arr1[i]);
int nv=ov+1;
map.put(arr1[i] , nv);
}else {
map.put(arr1[i] ,1);
}
}
int[] arr2=new int[n];
for(int i=0 ;i<n ;i++) {
arr2[i] =s.nextInt();
}
ArrayList list =new ArrayList<>();
for(int i=0 ;i<n ;i++ ) {
if(map.containsKey(arr2[i])) {
if(map.get(arr2[i]) > 0) {
list.add(arr2[i]);
int ov=map.get(arr2[i]);
int nv=ov-1;
map.put(arr2[i] ,nv);
}
}
}

System.out.print(list);
}

}

plz tell that test case for improvement

#2

hey @sameeksha
Read this line carefully
Output Format

Display the repeating elements in a comma separated manner enclosed in square brackets. The numbers should be sorted in increasing order.
just a change
sort ArrayList before printing

import java.util.*;

public class Main {
static Scanner s = new Scanner(System.in);

public static void main(String[] args) {
	int n = s.nextInt();
	int[] arr1 = new int[n];
	for (int i = 0; i < n; i++) {
		arr1[i] = s.nextInt();
	}
	HashMap<Integer, Integer> map = new HashMap<>();
	for (int i = 0; i < n; i++) {
		if (map.containsKey(arr1[i])) {
			int ov = map.get(arr1[i]);
			int nv = ov + 1;
			map.put(arr1[i], nv);
		} else {
			map.put(arr1[i], 1);
		}
	}
	int[] arr2 = new int[n];
	for (int i = 0; i < n; i++) {
		arr2[i] = s.nextInt();
	}
	ArrayList<Integer> list = new ArrayList<>();
	for (int i = 0; i < n; i++) {
		if (map.containsKey(arr2[i])) {
			if (map.get(arr2[i]) > 0) {
				list.add(arr2[i]);
				int ov = map.get(arr2[i]);
				int nv = ov - 1;
				map.put(arr2[i], nv);
			}
		}
	}

// sort list
Collections.sort(list);
System.out.println(list);
}
}
Please mark your all previous doubts as resolved in your course’s.