partition

Author: amejiarosario

linked-list/delete-middle-node.js

@@ -1,7 +1,7 @@
-
-
 const LinkedList = require('./linkedlist');
 
+// 2.3
+
 LinkedList.prototype.deleteMiddleNode = deleteNode;
 
 let list, node;

linked-list/linkedlist.js

@@ -1,8 +1,4 @@
-class Node {
-  constructor(data) {
-    this.data = data;
-  }
-}
+const Node = require('./node');
 
 class LinkedList {
   constructor() {

linked-list/node.js

@@ -0,0 +1,7 @@
+class Node {
+  constructor(data) {
+    this.data = data;
+  }
+}
+
+module.exports = Node;

linked-list/partition.js

@@ -0,0 +1,51 @@
+const LinkedList = require('./linkedlist');
+const Node = require('./node');
+
+LinkedList.prototype.partition = partition;
+
+function partition(value) {
+  let left = null, right = null;
+
+  // partition list
+  for(let current = this.head; current; current = current.next) {
+    const copy = new Node(current.data);
+    if(current.data < value) {
+      left = append(left, copy);
+    } else {
+      right = append(right, copy);
+    }
+  }
+
+  // merge list
+  let lastLeft;
+  for(lastLeft = left; lastLeft.next; lastLeft = lastLeft.next) {}
+  lastLeft.next = right;
+  this.head = left;
+}
+
+
+function append(head, node) {
+  if(head) { node.next = head; }
+  return node;
+}
+
+// testing
+
+function test() {
+  const list = new LinkedList();
+  list.add(1);
+  list.add(2);
+  list.add(10);
+  list.add(5);
+  list.add(8);
+  list.add(5);
+  list.add(3);
+
+  console.log(list.toString()); // 3 -> 5 -> 8 -> 5 -> 10 -> 2 -> 1
+
+  list.partition(5);
+
+  console.log(list.toString()); // 1 -> 2 -> 3 -> 10 -> 5 -> 8 -> 5
+}
+
+test();