updaintg the difference array

Leetcode/DifferenceArray.java

@@ -1,6 +1,15 @@
 import java.util.AbstractList;
+import java.util.*;
 
 class DifferenceArray {
+
+    public static void main(String[] args) {
+        DifferenceArray da = new DifferenceArray();
+       List<List<Integer>> la =  da.findDifference(new int[]{1,2,3,3}, new int[]{1,1,2,2});
+       for(List<Integer> a : la){
+        System.out.println(a);
+       }
+    }
 
     public List<List<Integer>> findDifference(int[] nums1, int[] nums2) {
 
@@ -22,16 +31,19 @@ public int size(){
             }
 
             private void process(){
-                first = new ArrayList<>();
-                second = new ArrayList<>();
-                byte[] m1 = new byte[2001];
-                byte[] m2 = new byte[2001];
+                first = new ArrayList<>(); //initialising the array
+                second = new ArrayList<>(); //initialising the array
+                //using size as 2001 coz the values of array range from -1000 to 1000
+                byte[] m1 = new byte[2001]; //initialising the byte array
+                byte[] m2 = new byte[2001]; //initialising the byte array
+                //marking all the numbers of array 2 in the byte
                 for(int i : nums2){
-                    m1[i+1000]=0b1;
+                    m1[i+1000]=0b1; // adding 1 for present value
                 }
+                //check in nums1 array if its present or not
                 for(int i : nums1){
                     int x = i+1000;
-                    if(m1[x]!=0b1){
+                    if(m1[x]!=0b1){ // if value not present then add in first 
                         m1[x] = 0b1;
                         first.add(i);
                     }