Fixes of the Nil pointer problem,

testing push 10000 elements at the end and get the 10000 elements and check it.

Author: lygstate

src/data-structures/size-balanced-tree.js

@@ -107,7 +107,7 @@
       NL  CL
     */
     node.right = childNode.left;
-    node.right.parent = node;
+    if (node.right !== Nil) node.right.parent = node;
     childNode.left = node;
     updateChild(node, childNode) //Access node.parent
     node.parent = childNode;
@@ -132,7 +132,7 @@
             CR  NR
     */
     node.left = childNode.right;
-    node.left.parent = node;
+    if (node.left !== Nil) node.left.parent = node;
     childNode.right = node;
     updateChild(node, childNode) //Access node.parent
     node.parent = childNode;
@@ -171,6 +171,7 @@
         node = node.left;
       } else {
         pos -= node.left.size;
+        --pos; //The node element should be decrement by 1
         node = node.right;
       }
     }

test/data-structures/size-balanced-tree.spec.js

@@ -81,5 +81,17 @@ describe('SBTree', function () {
     expect(root.left).toBe(Nil);
     updateChild(Nil, right);
     expect(right.parent).toBe(Nil);
+    checkNil();
+  });
+
+  it('push and get 100000 elements', function () {
+    var sTree = new SBTree();
+    for (var i = 0; i < 100000; ++i) {
+      sTree.push(i);
+    }
+    checkNil();
+    for (var i = 0; i < 100000; ++i) {
+      expect(sTree.get(i).value).toBe(i);
+    }
   });
 });