Chapter 2: Remove dups (careercup#9)

*  find middle node of a Singly Linked List

*  find middle node of a Singly Linked List

*  find middle node of a Singly Linked List

* add find-middle node tests

* Delete middle Node of Linked List

* correct2-3-Delete Middle Node

*  add solution for access to the head  / or access to middle-node

* 2-2: rturn Kth to Last

* add for loop for craating new node in  beforeEach for tests

* 2-8: Detection Loop in SLL

*  2-1-remove duplicate nodes

Author: Raziyehbazargan

README.md

@@ -16,6 +16,7 @@
 - [ ] 1.9 - String Rotation
 
 #### Chapter 2
+- [x] 2.1 - [Remove Duplicate](lib/data-structures/chapter-2/2_1.js)
 - [x] 2.2 - [Return Kth to Last](lib/data-structures/chapter-2/2_2.js)
 - [x] 2.3 - [Delete Middle Node](lib/data-structures/chapter-2/2_3.js)
 - [x] 2.8 - [Detection Loop](lib/data-structures/chapter-2/2_8.js)

lib/data-structures/chapter-2/2_1.js

@@ -0,0 +1,23 @@
+var SLL = require('./helper.js');
+
+  SLL.prototype.removeDups = function(head) {
+
+   if (head === null || head.next === null) {
+      return null;
+    }
+
+   var current = head;
+
+   while(current !== null) {
+      var runner = current;
+      while (runner.next !== null) {
+        if (runner.next.data === current.data) {
+          runner.next = runner.next.next;
+          this.length--;
+        } else {
+          runner = runner.next;
+        }
+      }
+      current = current.next;
+    }
+  };

test/data-structures/chapter-2/2_1_Spec.js

@@ -0,0 +1,24 @@
+require('../../test_helper');
+
+describe('2.1 #removeDups', function () {
+  describe('remove duplicate from linkedlist', function () {
+    var sll;
+    beforeEach(function() {
+      sll = new MyLinkedList();
+      for(var i=1; i < 6; i++) {
+        sll.addNode( i + 'Node', null);
+      }
+      //create duplicate in linkedlist
+      sll.addNode('5Node', null);
+    });
+
+    afterEach(function() {
+      sll = null;
+    });
+
+    it('should delete duplicate node from SLL', function () {
+      sll.removeDups(sll.head);
+      expect(sll).length.to.be(5);
+    });
+  });
+});