From c3a961840d82868d51165a6b023b30b66cf46547 Mon Sep 17 00:00:00 2001
From: Oleksii Trekhleb <trehleb@gmail.com>
Date: Wed, 13 Jun 2018 06:39:18 +0300
Subject: [PATCH] Fix BST removal method.

---
 src/data-structures/tree/avl-tree/AvlTree.js           |  8 ++++++++
 .../tree/avl-tree/__test__/AvlTRee.test.js             | 10 ++++++++++
 .../tree/binary-search-tree/BinarySearchTree.js        |  2 +-
 .../tree/binary-search-tree/BinarySearchTreeNode.js    |  4 ++--
 .../__test__/BinarySearchTree.test.js                  |  8 ++++----
 .../__test__/BinarySearchTreeNode.test.js              |  8 ++++----
 .../tree/red-black-tree/RedBlackTree.js                |  2 +-
 7 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/src/data-structures/tree/avl-tree/AvlTree.js b/src/data-structures/tree/avl-tree/AvlTree.js
index b4b86ea4..51e6a05f 100644
--- a/src/data-structures/tree/avl-tree/AvlTree.js
+++ b/src/data-structures/tree/avl-tree/AvlTree.js
@@ -16,6 +16,14 @@ export default class AvlTree extends BinarySearchTree {
     }
   }
 
+  /**
+   * @param {*} value
+   * @return {boolean}
+   */
+  remove(value) {
+    throw new Error(`Can't remove ${value}. Remove method is not implemented yet`);
+  }
+
   /**
    * @param {BinarySearchTreeNode} node
    */
diff --git a/src/data-structures/tree/avl-tree/__test__/AvlTRee.test.js b/src/data-structures/tree/avl-tree/__test__/AvlTRee.test.js
index 5be7d119..fb1f3ee4 100644
--- a/src/data-structures/tree/avl-tree/__test__/AvlTRee.test.js
+++ b/src/data-structures/tree/avl-tree/__test__/AvlTRee.test.js
@@ -229,4 +229,14 @@ describe('AvlTree', () => {
     expect(tree.toString()).toBe('10,15,18,30,35,40,42,43,45,47');
     expect(tree.root.height).toBe(3);
   });
+
+  it('should throw an error when trying to remove the node', () => {
+    const removeNodeAvlTree = () => {
+      const tree = new AvlTree();
+
+      tree.remove(1);
+    };
+
+    expect(removeNodeAvlTree).toThrowError();
+  });
 });
diff --git a/src/data-structures/tree/binary-search-tree/BinarySearchTree.js b/src/data-structures/tree/binary-search-tree/BinarySearchTree.js
index e70950f9..b9e2ddad 100644
--- a/src/data-structures/tree/binary-search-tree/BinarySearchTree.js
+++ b/src/data-structures/tree/binary-search-tree/BinarySearchTree.js
@@ -29,7 +29,7 @@ export default class BinarySearchTree {
 
   /**
    * @param {*} value
-   * @return {BinarySearchTreeNode}
+   * @return {boolean}
    */
   remove(value) {
     return this.root.remove(value);
diff --git a/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js b/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
index d6fe4bae..9ad74483 100644
--- a/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
+++ b/src/data-structures/tree/binary-search-tree/BinarySearchTreeNode.js
@@ -81,7 +81,7 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {
 
   /**
    * @param {*} value
-   * @return {BinarySearchTreeNode}
+   * @return {boolean}
    */
   remove(value) {
     const nodeToRemove = this.find(value);
@@ -120,7 +120,7 @@ export default class BinarySearchTreeNode extends BinaryTreeNode {
       }
     }
 
-    return nodeToRemove;
+    return true;
   }
 
   /**
diff --git a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTree.test.js b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTree.test.js
index 593014d8..981a118d 100644
--- a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTree.test.js
+++ b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTree.test.js
@@ -43,13 +43,13 @@ describe('BinarySearchTree', () => {
 
     expect(bst.toString()).toBe('5,10,20');
 
-    const removedNode1 = bst.remove(5);
+    const removed1 = bst.remove(5);
     expect(bst.toString()).toBe('10,20');
-    expect(removedNode1.value).toBe(5);
+    expect(removed1).toBeTruthy();
 
-    const removedNode2 = bst.remove(20);
+    const removed2 = bst.remove(20);
     expect(bst.toString()).toBe('10');
-    expect(removedNode2.value).toBe(20);
+    expect(removed2).toBeTruthy();
   });
 
   it('should insert object values', () => {
diff --git a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
index 35a7fc53..a353c1f1 100644
--- a/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
+++ b/src/data-structures/tree/binary-search-tree/__test__/BinarySearchTreeNode.test.js
@@ -125,13 +125,13 @@ describe('BinarySearchTreeNode', () => {
 
     expect(bstRootNode.toString()).toBe('5,10,20');
 
-    const removedNode1 = bstRootNode.remove(5);
+    const removed1 = bstRootNode.remove(5);
     expect(bstRootNode.toString()).toBe('10,20');
-    expect(removedNode1.value).toBe(5);
+    expect(removed1).toBeTruthy();
 
-    const removedNode2 = bstRootNode.remove(20);
+    const removed2 = bstRootNode.remove(20);
     expect(bstRootNode.toString()).toBe('10');
-    expect(removedNode2.value).toBe(20);
+    expect(removed2).toBeTruthy();
   });
 
   it('should remove nodes with one child', () => {
diff --git a/src/data-structures/tree/red-black-tree/RedBlackTree.js b/src/data-structures/tree/red-black-tree/RedBlackTree.js
index 2bd3afd4..6bb47130 100644
--- a/src/data-structures/tree/red-black-tree/RedBlackTree.js
+++ b/src/data-structures/tree/red-black-tree/RedBlackTree.js
@@ -34,7 +34,7 @@ export default class RedBlackTree extends BinarySearchTree {
 
   /**
    * @param {*} value
-   * @return {BinarySearchTreeNode}
+   * @return {boolean}
    */
   remove(value) {
     throw new Error(`Can't remove ${value}. Remove method is not implemented yet`);