Tree #DataStructureAlgorithms

_tree.js

// Tree Node Definition
function TreeNode(val) {
    this.val = val;
    this.left = this.right = null;
}

// Tree Creation
var t = new TreeNode(10)
t.left = new TreeNode(-2)
t.right = new TreeNode(6)
t.left.left = new TreeNode(8)
t.left.right = new TreeNode(-4)
t.right.left = new TreeNode(7)
t.right.right = new TreeNode(5)

check-if-binary-tree-is-a-sum-tree.js

// Check if a given binary tree is a sum tree
var sumTree = function(root) {
    if (root === null) {
        return true
    }
    if (root.left === null && root.right === null) {
        return true
    }
    return root.val === addNodes(root.left) + addNodes(root.right)
}
var addNodes = function(root) {
    if (root === null) {
        return 0
    }
    return root.val + addNodes(root.left) + addNodes(root.right)
}

check-if-binary-tree-is-binary-search-tree.js

// Check if a binary tree is a binary search tree (BST)
function checkIfBinaryTreeIsBST (root, min = Number.MIN_VALUE, max = Number.MAX_VALUE) {
	if (root === null) {
		return true
	}
	if (root.val < min || root.val > max) {
		return false
	}
	return checkIfBinaryTreeIsBST(root.left, min, root.val - 1) && checkIfBinaryTreeIsBST(root.right, root.val + 1, max)
}

convert-binary-tree-to-sum-tree.js

// Convert binary tree to a sum tree
var convertToSumTree = function(root) {
    if (root === null) {
        return 0
    }
    var temp = root.val
    root.val = convertToSumTree(root.left) + convertToSumTree(root.right)
    return root.val + temp
}

get-size-of-tree.js

// Get size of a tree
function size(root) {
	if (root === null) {
		return 0
	} else {
		return size(root.left) + size(root.right) + 1
	}
}

print-tree.js

// Print Tree
function printTree(root) {
    if (root === null) {
        return
    }
    printTree(root.left)
    process.stdout.write(`${root.val.toString()} `);
    printTree(root.right)
}