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The Coding Aviator
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e736179720
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5fb179a6ef
@ -37,7 +37,7 @@ tests:
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- text: An empty tree returns a height of <code>-1</code>.
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testString: assert((function() { var test = false; if (typeof BinarySearchTree !== 'undefined') { test = new BinarySearchTree() } else { return false; }; if (typeof test.findMaxHeight !== 'function') { return false; }; return (test.findMaxHeight() == -1); })(), 'An empty tree returns a height of <code>-1</code>.');
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- text: The <code>isBalanced</code> method returns true if the tree is a balanced binary search tree.
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testString: assert((function() { var test = false; if (typeof BinarySearchTree !== 'undefined') { test = new BinarySearchTree() } else { return false; }; if (typeof test.isBalanced !== 'function') { return false; }; test.add(4); test.add(1); test.add(7); test.add(87); test.add(34); test.add(45); test.add(73); test.add(8); return test.isBalanced(); })(), 'The <code>isBalanced</code> method returns true if the tree is a balanced binary search tree.');
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testString: assert((function() { var test = false; if (typeof BinarySearchTree !== 'undefined') { test = new BinarySearchTree() } else { return false; }; if (typeof test.isBalanced !== 'function') { return false; }; test.add(4); test.add(1); test.add(7); test.add(87); test.add(34); test.add(45); test.add(73); test.add(8); return !test.isBalanced(); })(), 'The <code>isBalanced</code> method returns true if the tree is a balanced binary search tree.');
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```
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@ -110,55 +110,78 @@ BinarySearchTree.prototype = {
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```js
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var displayTree = (tree) => console.log(JSON.stringify(tree, null, 2));
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function Node(value) {
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this.value = value;
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this.left = null;
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this.right = null;
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this.value = value;
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this.left = null;
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this.right = null;
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}
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function BinarySearchTree() {
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this.root = null;
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// change code below this line
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this.findMinHeight = function(root = this.root) {
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if (root === null) {
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return -1;
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} else if (root.left === null && root.right === null) {
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return 0;
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} else if (root.left == null) {
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return (this.findMinHeight(root.right) + 1);
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} else if (root.right == null) {
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return (this.findMinHeight(root.left) + 1);
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} else {
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return Math.min(this.findMinHeight(root.left), this.findMinHeight(root.right)) + 1;
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}
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}
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this.findMaxHeight = function(root = this.root) {
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if (root === null) {
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return -1;
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} else if (root.left === null && root.right === null) {
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return 0;
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} else if (root.left == null) {
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return (this.findMaxHeight(root.right) + 1);
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} else if (root.right == null) {
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return (this.findMaxHeight(root.left) + 1);
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} else {
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return Math.max(this.findMaxHeight(root.left), this.findMaxHeight(root.right)) + 1;
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}
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}
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this.isBalanced = function(root = this.root) {
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if (root === null || root.left === null || root.right === null) {
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return false;
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}
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let l = this.findMaxHeight(root.left);
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let r = this.findMaxHeight(root.right);
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let difference = Math.abs(r - l);
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if (difference <= 1 && this.isBalanced(root.left) && this.isBalanced(root.right)) {
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return false;
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}
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return true;
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}
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// change code above this line
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this.root = null;
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// change code below this line
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// change code above this line
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this.findMinHeight = function(root = this.root) {
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// empty tree.
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if(root === null) {
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return -1;
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}
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// leaf node.
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if(root.left === null && root.right === null) {
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return 0;
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}
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if(root.left === null){
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return this.findMinHeight(root.right) + 1;
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}
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if(root.right === null){
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return this.findMinHeight(root.left) + 1;
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}
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const lHeight = this.findMinHeight(root.left);
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const rHeight = this.findMinHeight(root.right);
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return Math.min(lHeight, rHeight) + 1;
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};
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this.findMaxHeight = function(root = this.root) {
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// empty tree.
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if(root === null) {
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return -1;
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}
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// leaf node.
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if(root.left === null && root.right === null) {
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return 0;
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}
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if(root.left === null){
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return this.findMaxHeight(root.right) + 1;
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}
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if(root.right === null){
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return this.findMaxHeight(root.left) + 1;
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}
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const lHeight = this.findMaxHeight(root.left);
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const rHeight = this.findMaxHeight(root.right);
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return Math.max(lHeight, rHeight) + 1;
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};
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this.isBalanced = function(root = this.root) {
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if(root === null) {
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return true;
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}
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if(root.left === null && root.right === null){
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return true;
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}
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if(root.left === null) {
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return this.findMaxHeight(root.right) <= 0;
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}
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if(root.right === null) {
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return this.findMaxHeight(root.left) <= 0;
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}
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const lHeight = this.findMaxHeight(root.left);
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const rHeight = this.findMaxHeight(root.right);
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if(Math.abs(lHeight - rHeight) > 1){
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return false;
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}
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return this.isBalanced(root.left) && this.isBalanced(root.right);
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};
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}
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```
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</section>
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