sum list done

Author: rampatra

src/main/java/com/ctci/linkedlists/SumLists.java

@@ -0,0 +1,69 @@
+package com.ctci.linkedlists;
+
+import static com.ctci.linkedlists.Node.printList;
+
+/**
+ * @author rampatra
+ * @since 2019-01-31
+ */
+public class SumLists {
+
+    private static Node sumLists(Node num1, Node num2) {
+        int carry = 0;
+        int sum;
+        Node sumList = null, curr = null;
+        while (num1 != null || num2 != null) {
+            sum = ((num1 == null) ? 0 : num1.val) + ((num2 == null) ? 0 : num2.val) + carry;
+            carry = sum / 10;
+            if (sumList == null) {
+                sumList = new Node(sum % 10);
+                curr = sumList;
+            } else {
+                curr.next = new Node(sum % 10);
+                curr = curr.next;
+            }
+            if (num1 != null) num1 = num1.next;
+            if (num2 != null) num2 = num2.next;
+        }
+        if (carry != 0) {
+            curr.next = new Node(carry);
+        }
+        return sumList;
+    }
+    
+    public static void main(String[] args) {
+        Node l1 = new Node(9);
+        l1.next = new Node(9);
+        l1.next.next = new Node(9);
+
+        Node l2 = new Node(9);
+        l2.next = new Node(9);
+        l2.next.next = new Node(9);
+
+        printList(l1);
+        printList(l2);
+        printList(sumLists(l1, l2));
+        System.out.println("-----------");
+
+        l1 = new Node(9);
+        l1.next = new Node(9);
+
+        l2 = new Node(9);
+        l2.next = new Node(9);
+        l2.next.next = new Node(9);
+
+        printList(l1);
+        printList(l2);
+        printList(sumLists(l1, l2));
+        System.out.println("-----------");
+
+        l1 = null;
+        l2 = new Node(9);
+        l2.next = new Node(9);
+        l2.next.next = new Node(8);
+
+        printList(l1);
+        printList(l2);
+        printList(sumLists(l1, l2));
+    }
+}