Discussion on Tree: Height of a Binary Tree Challenge

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5 days ago+ 0 comments

The code provided for Javascript is broken.

You can copy this wrapper and use typescript. Type your solution inside the treeHeight function.

'use strict';

process.stdin.resume();
process.stdin.setEncoding('utf-8');
// process.stdin.setEncoding('ascii');
let inputString: string = '';
let inputLines: string[] = [];
let currentLine: number = 0;
process.stdin.on('data', function(inputStdin: string): void {
    inputString += inputStdin;
});

process.stdin.on('end', function(): void {
    inputLines = inputString.split(/\s/);
    inputString = '';
    solution();
});

function readLine(): string {
    return inputLines[currentLine++];
}

class TreeNode {
    data:number;
    left:null|TreeNode;
    right:null|TreeNode;
    constructor(data:number){
    this.data = data;
    this.left = null;
    this.right = null;
    }
}

class Tree {
    root:TreeNode|null;
    constructor() {
    this.root = null;
    }
    insert(node:TreeNode, data:number) {
        if (node == null){
            node = new TreeNode(data);
        }
        else if (data < node.data){
            node.left  = this.insert(node.left, data);
        }
        else{
            node.right = this.insert(node.right, data);   
        }

        return node;
    }
}


// This is a "method-only" submission.
// You only need to complete this method.

function treeHeight(root:TreeNode):string {
	return "Your solution in here";

}


function solution() {

    var tree = new Tree();
    var n = parseInt(readLine());

    for (var i=0; i<n; i++) {
        var m = parseInt(readLine());
        tree.root = tree.insert(tree.root, m);
    }

    var height = treeHeight(tree.root);
    process.stdout.write(height);
}

1 week ago+ 0 comments

Python 3, breadth-first traversal, without recursion

def height(root):
    nodes = {0 : [root]}
    h = 0
    while nodes.get(h):
        nodes[h+1] = []
        for node in nodes[h]:
            if node.left:
                nodes[h+1].append(node.left)
            if node.right:
                nodes[h+1].append(node.right)
        h += 1
    return max(nodes.keys()) - 1

1 week ago+ 0 comments

simple c++ recursive solution

int height(Node* root) {
       if(root==NULL){return -1;}
       else{
           int left = height(root->left);
           int right = height(root->right);
           return max(left,right)+1;
       }
    }

4 weeks ago+ 1 comment

(JavaScript) Bug report on building a tree. For the example:

7
3 5 2 1 4 6 7

It creates an _stdin_array = [ '7', '3 5 2 1 4 6 7' ] but the method readLine() tries to read n lines/elements after reding the first line(_stdin_array[0]) to assign the value to n but we only have one more line/element. Thus, the first node is created correctly because parseInt('3 5 2 1 4 6 7' ); but later tries to get _stdin_array[2] and _stdin_array[3] and so on, elements that not exists in the array and it gets an undefined and parseInt(undefined) returns a NaN. You end up with a right-loaded tree with mostly NaN data values.

1 month ago+ 0 comments

In Swift

code gave run time because boilerplate code. Hackerrank must fix this line: " root = tree.insert(root: root, data: Int(readLine()!)!) ".

    func getHeight(root: Node?) -> Int {
        if root == nil {
                return -1
        } else {

                let left = getHeight(root: root?.left)
                let right = getHeight(root: root?.right)

                if left > right {
                        return left + 1
                } else {
                        return right + 1
                }
         }
    }

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