From e2c68f4587c114fda37a0dc9ee2b5da78b9b04c2 Mon Sep 17 00:00:00 2001
From: KamillaKhabibrakhmanova <venessiel@gmail.com>
Date: Wed, 29 Jun 2016 21:43:41 -0400
Subject: [PATCH 1/3] added binary search tree

---
 DataStructures/BinarySearchTree.js | 123 +++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 DataStructures/BinarySearchTree.js

diff --git a/DataStructures/BinarySearchTree.js b/DataStructures/BinarySearchTree.js
new file mode 100644
index 0000000..9743a28
--- /dev/null
+++ b/DataStructures/BinarySearchTree.js
@@ -0,0 +1,123 @@
+var BST = function(val) {
+	this.val = val;
+};
+
+BST.prototype.contains = function(val) {
+	var curr = this;
+	var found = false;
+	
+	while(!found && curr) {
+		if (val === curr.val) {
+			found = true;
+		}
+		if (val > curr.val){
+			curr = curr.right;
+		} else if (val < curr.val) {
+			curr = curr.left;
+		}
+	}
+	return found;
+};
+
+BST.prototype.insert = function(val){
+	var valNode = new BST(val);
+	
+ 	while(true) {
+ 		if (val < this.val) {
+ 			if (!this.left) {
+ 				this.left = valNode;
+ 				break;
+ 			} else {
+ 				return this.left.insert(val);
+ 			}
+ 		} else if (val > this.val) {
+ 			if (!this.right) {
+ 				this.right = valNode;
+ 				break;
+ 			} else {
+ 				return this.right.insert(val)
+ 			}
+ 		} else return;
+ 	}
+};
+
+BST.prototype.traverse = function(process){
+	function processNode(node) {
+		if (node.left) {
+			processNode(node.left)
+		}
+		process.call(this, node.val);
+		if (node.right) {
+			processNode(node.right);
+		}
+	}
+	processNode(this);
+};
+
+BST.prototype.size = function(){
+	var length = 0;
+	
+	this.traverse(function(node){
+		length ++;
+	});
+	return length;
+};
+
+BST.prototype.toArray = function(){
+	var array = [];
+	
+	this.traverse(function(node){
+		array.push(node.val);
+	});
+	return array;
+};
+
+BST.prototype.remove = function(value) {
+	var curr = this;
+	var parent = null;
+	var found = false;
+	var direction = null;
+	while (!found) {
+	 	if ( value === curr.val) {
+	 		found = true;
+	 	}
+	 	if (value < curr.val) {
+	 		parent = curr;
+	 		direction = 'left';
+	 		curr = curr.left;
+	 	} else if (value > curr.val) {
+	 		parent = curr;
+	 		direction = 'right';
+	 		curr = curr.right;
+	 	}
+	}
+	//no children - just remove node
+	if (!curr.left && !curr.right) {
+		parent[direction] = null;
+	//two children
+	} else if (curr.left && curr.right) {
+		var opposite = direction === 'right' ? 'left' : 'right';
+		var last = curr[opposite];
+		while (last[opposite]) {
+			last = last[opposite];
+		}
+		curr.val = last.val;
+		
+		if (direction === 'left') {
+			last = curr.right;
+			while (last.right) {
+				last = last.right;
+			}
+			curr.val = last.val;
+		}
+	//one child - replace node with child
+	} else {
+		if (direction === 'left') {
+			if (curr.left) parent.left = curr.left;
+			else parent.left = curr.right;
+		} else {
+			if (curr.left) parent.right = curr.left;
+			else parent.right = curr.right;
+		}
+	}
+}
\ No newline at end of file

From a1352bddddcec31baa6d1d5a2d36e2d9ab5387b7 Mon Sep 17 00:00:00 2001
From: KamillaKhabibrakhmanova <venessiel@gmail.com>
Date: Wed, 29 Jun 2016 23:03:44 -0400
Subject: [PATCH 2/3] woops this is the right one

---
 Chapter4-TreesAndGraphs/4.1-IsBalanced.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 Chapter4-TreesAndGraphs/4.1-IsBalanced.js

diff --git a/Chapter4-TreesAndGraphs/4.1-IsBalanced.js b/Chapter4-TreesAndGraphs/4.1-IsBalanced.js
new file mode 100644
index 0000000..d6d7ac4
--- /dev/null
+++ b/Chapter4-TreesAndGraphs/4.1-IsBalanced.js
@@ -0,0 +1,22 @@
+/*
+Problem: Implement a function to check if a binary tree is balanced. 
+Here that is defined as a tree that the heights of the two subtrees of any node never differ by more than one.
+*/
+
+//building off of the binary search tree defined in the structures folder
+
+BST.prototype.isBalanced = function() {
+	console.log(this);
+	function hasRightAndLeft(node){
+		if (!node.right && !node.left) return true;
+		else if (node.right && node.left) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	while (this.left && this.right) {
+		return (hasRightAndLeft(this.left) && hasRightAndLeft(this.right))
+	}
+};
\ No newline at end of file

From 411e4491610159e1ed62baf7791fa61b5c6ab0d5 Mon Sep 17 00:00:00 2001
From: KamillaKhabibrakhmanova <venessiel@gmail.com>
Date: Wed, 29 Jun 2016 23:04:52 -0400
Subject: [PATCH 3/3] remove console log

---
 Chapter4-TreesAndGraphs/4.1-IsBalanced.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Chapter4-TreesAndGraphs/4.1-IsBalanced.js b/Chapter4-TreesAndGraphs/4.1-IsBalanced.js
index d6d7ac4..17d16b0 100644
--- a/Chapter4-TreesAndGraphs/4.1-IsBalanced.js
+++ b/Chapter4-TreesAndGraphs/4.1-IsBalanced.js
@@ -6,7 +6,7 @@ Here that is defined as a tree that the heights of the two subtrees of any node
 //building off of the binary search tree defined in the structures folder
 
 BST.prototype.isBalanced = function() {
-	console.log(this);
+	//check if node has both right & left (or neither) to see if balanced
 	function hasRightAndLeft(node){
 		if (!node.right && !node.left) return true;
 		else if (node.right && node.left) {