Add merge two sorted lists solution

Author: sudheerj

src/java1/algorithms/linkedlist/MergeTwoSortedLists.java

@@ -0,0 +1,78 @@
+package java1.algorithms.linkedlist;
+
+public class MergeTwoSortedLists {
+    //TC: O(m+n) SC:O(1)
+    private static Node mergeSortedLists(Node l1, Node l2) {
+        Node newHead = new Node(-1);
+        Node p1 = l1, p2 = l2, currNode = newHead;
+        while(p1 != null & p2 != null) {
+            if(p1.value < p2.value) {
+                currNode.next = p1;
+                p1 = p1.next;
+            } else {
+                currNode.next = p2;
+                p2 = p2.next;
+            }
+            currNode = currNode.next;
+        }
+        if(p1 == null) {
+            currNode.next = p2;
+        }
+        if(p2 == null) {
+            currNode.next = p1;
+        }
+        return newHead.next;
+    }
+
+    //Recursive approach
+    private static Node mergeSortedListsRecursion(Node l1, Node l2) {
+        if(l1 == null) return l2;
+        if(l2 == null) return l1;
+
+        if(l1.value < l2.value) {
+            l1.next = mergeSortedListsRecursion(l1.next, l2);
+            return l1;
+        } else {
+            l2.next = mergeSortedListsRecursion(l1, l2.next);
+            return l2;
+        }
+    }
+
+    private static void printLinkedlist(Node head) {
+        while(head != null) {
+            System.out.println(head.value + " ");
+            head = head.next;
+        }
+    }
+    public static void main(String[] args) {
+        Node headNode1 = new Node(10);
+        Node node2 = new Node(20);
+        Node node3 = new Node(30);
+        Node node4 = new Node(40);
+        Node node5 = new Node(50);
+        Node node6 = new Node(60);
+
+        Node headNode2 = new Node(5);
+        Node node7 = new Node(15);
+        Node node8 = new Node(25);
+        Node node9 = new Node(35);
+        Node node10 = new Node(45);
+        Node node11 = new Node(55);
+ 
+
+        headNode1.setNext(node2);
+        node2.setNext(node3);
+        node3.setNext(node4);
+        node4.setNext(node5);
+        node5.setNext(node6);
+
+        headNode2.setNext(node7);
+        node7.setNext(node8);
+        node8.setNext(node9);
+        node9.setNext(node10);
+        node10.setNext(node11);
+
+        printLinkedlist(mergeSortedLists(headNode1, headNode2));
+        printLinkedlist(mergeSortedListsRecursion(headNode1, headNode2));
+    }
+}

src/javascript/algorithms/linkedlist/mergeTwoSortedLists.js

@@ -0,0 +1,81 @@
+class Node {
+    constructor(value) {
+        this.value = value;
+        this.next = null;
+    }
+
+    setNext(next) {
+        this.next = next;
+    }
+}
+
+//TC: O(m+n) SC:O(1)
+function mergeTwoSortedLists(l1, l2) {
+    let newHead = new Node(-1);
+    let currNode = newHead; 
+
+    while(l1 != null && l2 != null) {
+        if(l1.value < l2.value) {
+            currNode.next = l1;
+            l1 = l1.next;
+        } else {
+            currNode.next = l2;
+            l2 = l2.next;
+        }
+        currNode = currNode.next;
+    }
+    return newHead.next;
+}
+
+//Recursion approach: TC: O(m+n) SC:O(m+n)
+function mergeTwoSortedListsRecursion(l1, l2){
+    if(l1 == null) return l2;
+    if(l2 == null) return l1;
+
+    if(l1.value < l2.value) {
+        l1.next = mergeTwoSortedListsRecursion(l1.next, l2);
+        return l1;
+    } else {
+        l2.next = mergeTwoSortedListsRecursion(l1, l2.next);
+        return l2;
+    }
+}
+
+function printLinkedList(head) {
+    let temp = head;
+    while(temp != null) {
+        console.log(temp.value + " ");
+        temp = temp.next;
+    }
+
+}
+
+let headNode1 = new Node(10);
+let node2 = new Node(20);
+let node3 = new Node(30);
+let node4 = new Node(40);
+let node5 = new Node(50);
+let node6 = new Node(60);
+
+let headNode2 = new Node(5);
+let node7 = new Node(15);
+let node8 = new Node(25);
+let node9 = new Node(35);
+let node10 = new Node(45);
+let node11 = new Node(55);
+
+
+headNode1.setNext(node2);
+node2.setNext(node3);
+node3.setNext(node4);
+node4.setNext(node5);
+node5.setNext(node6);
+
+headNode2.setNext(node7);
+node7.setNext(node8);
+node8.setNext(node9);
+node9.setNext(node10);
+node10.setNext(node11);
+
+printLinkedList(mergeTwoSortedLists(headNode1, headNode2));
+printLinkedList(mergeTwoSortedListsRecursion(headNode1, headNode2));