Merge pull request neetcode-gh#192 from GaneshanNT/main

Java solution added for Linked List problems

Author: neetcode-gh

java/2-Add-Two-Numbers.java

@@ -0,0 +1,49 @@
+/*
+    Name - Add Two Numbers
+    Link - https://leetcode.com/problems/add-two-numbers/
+    Time Complexity - O(m + n)
+    Space Complexity - o(1)
+    Note - make use of modulo (get remainder) and division (get quotient)
+*/
+
+class Solution {
+    public ListNode addTwoNumbers(ListNode first, ListNode second) {
+        int q = 0;
+        int r = 0;
+        int sum = 0;
+        ListNode head = null;
+        ListNode temp = null;
+        while (first != null || second != null) {
+            sum = q + (((first != null) ? first.val : 0) + ((second != null) ? second.val : 0));
+            r = sum % 10;
+            q = sum / 10;
+            ListNode newNode = new ListNode(r);
+            if (head == null) {
+                head = newNode;
+            } else {
+                temp = head;
+                while(temp.next!=null){
+                    temp=temp.next;
+                }
+                temp.next = newNode;
+                newNode.next = null;
+            }
+            if (first != null) {
+                first = first.next;
+            }
+            if (second != null) {
+                second = second.next;
+            }
+        }
+        if(q>0){
+            ListNode newNode = new ListNode(q);
+            temp = head;
+                while(temp.next!=null){
+                    temp=temp.next;
+                }
+                temp.next = newNode;
+                newNode.next = null;
+        }
+        return head;
+    }
+}