Update find-the-minimum-and-maximum-value-in-a-binary-search-tree.english.md (#35057)

Added solution which has been tested and confirmed to pass all tests
This commit is contained in:
Dan B
2019-03-05 06:44:59 -08:00
committed by Tom
parent 8bb76a4eb6
commit 73e6e13243

View File

@ -108,6 +108,176 @@ BinarySearchTree.prototype = {
<section id='solution'>
```js
// solution required
var displayTree = tree => console.log(JSON.stringify(tree, null, 2));
function Node(value) {
this.value = value;
this.left = null;
this.right = null;
}
function BinarySearchTree() {
this.root = null;
this.findMin = function() {
// Empty tree.
if (!this.root) {
return null;
}
let currentNode = this.root;
while (currentNode.left) {
currentNode = currentNode.left;
}
return currentNode.value;
};
this.findMax = function() {
// Empty tree.
if (!this.root) {
return null;
}
let currentNode = this.root;
while (currentNode.right) {
currentNode = currentNode.right;
}
return currentNode.value;
};
this.add = function(value) {
// Empty tree.
if (!this.root) {
this.root = new Node(value);
return undefined;
}
return this.addNode(this.root, value);
};
this.addNode = function(node, value) {
// Check if value already exists.
if (node.value === value) return null;
if (value < node.value) {
if (node.left) {
return this.addNode(node.left, value);
} else {
node.left = new Node(value);
return undefined;
}
} else {
if (node.right) {
return this.addNode(node.right, value);
} else {
node.right = new Node(value);
return undefined;
}
}
};
this.isPresent = function(value) {
if (!this.root) {
return null;
}
return this.isNodePresent(this.root, value);
};
this.isNodePresent = function(node, value) {
if (node.value === value) return true;
if (value < node.value) {
return node.left ? this.isNodePresent(node.left, value) : false;
} else {
return node.right ? this.isNodePresent(node.right, value) : false;
}
return false;
};
this.findMinHeight = function() {
if (!this.root) {
return -1;
}
let heights = {};
let height = 0;
this.traverseTree(this.root, height, heights);
return Math.min(...Object.keys(heights));
};
this.findMaxHeight = function() {
if (!this.root) {
return -1;
}
let heights = {};
let height = 0;
this.traverseTree(this.root, height, heights);
return Math.max(...Object.keys(heights));
};
this.traverseTree = function(node, height, heights) {
if (node.left === null && node.right === null) {
return (heights[height] = true);
}
if (node.left) {
this.traverseTree(node.left, height + 1, heights);
}
if (node.right) {
this.traverseTree(node.right, height + 1, heights);
}
};
this.isBalanced = function() {
return this.findMaxHeight() > this.findMinHeight() + 1;
};
// DFS tree traversal.
this.inorder = function() {
if (!this.root) return null;
let result = [];
function traverseInOrder(node) {
if (node.left) traverseInOrder(node.left);
result.push(node.value);
if (node.right) traverseInOrder(node.right);
}
traverseInOrder(this.root);
return result;
};
this.preorder = function() {
if (!this.root) return null;
let result = [];
function traverseInOrder(node) {
result.push(node.value);
if (node.left) traverseInOrder(node.left);
if (node.right) traverseInOrder(node.right);
}
traverseInOrder(this.root);
return result;
};
this.postorder = function() {
if (!this.root) return null;
let result = [];
function traverseInOrder(node) {
if (node.left) traverseInOrder(node.left);
if (node.right) traverseInOrder(node.right);
result.push(node.value);
}
traverseInOrder(this.root);
return result;
};
// BFS tree traversal.
this.levelOrder = function() {
if (!this.root) return null;
let queue = [this.root];
let result = [];
while (queue.length) {
let node = queue.shift();
result.push(node.value);
if (node.left) queue.push(node.left);
if (node.right) queue.push(node.right);
}
return result;
};
this.reverseLevelOrder = function() {
if (!this.root) return null;
let queue = [this.root];
let result = [];
while (queue.length) {
let node = queue.shift();
result.push(node.value);
if (node.right) queue.push(node.right);
if (node.left) queue.push(node.left);
}
return result;
};
// Delete a leaf node.
}
let bst = new BinarySearchTree();
```
</section>