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/* Binary Search Tree */ | |
class Node { | |
constructor(data, left = null, right = null) { | |
this.data = data; | |
this.left = left; | |
this.right = right; | |
} | |
} | |
class BST { | |
constructor() { | |
this.root = null; | |
} | |
add(data) { | |
const node = this.root; | |
if (node === null) { | |
this.root = new Node(data); | |
return; | |
} else { | |
const searchTree = function(node) { | |
if (data < node.data) { | |
if (node.left === null) { | |
node.left = new Node(data); | |
return; | |
} else if (node.left !== null) { | |
return searchTree(node.left); | |
} | |
} else if (data > node.data) { | |
if (node.right === null) { | |
node.right = new Node(data); | |
return; | |
} else if (node.right !== null) { | |
return searchTree(node.right); | |
} | |
} else { | |
return null; | |
} | |
}; | |
return searchTree(node); | |
} | |
} | |
findMin() { | |
let current = this.root; | |
while (current.left !== null) { | |
current = current.left; | |
} | |
return current.data; | |
} | |
findMax() { | |
let current = this.root; | |
while (current.right !== null) { | |
current = current.right; | |
} | |
return current.data; | |
} | |
find(data) { | |
let current = this.root; | |
while (current.data !== data) { | |
if (data < current.data) { | |
current = current.left; | |
} else { | |
current = current.right; | |
} | |
if (current === null) { | |
return null; | |
} | |
} | |
return current; | |
} | |
isPresent(data) { | |
let current = this.root; | |
while (current) { | |
if (data === current.data) { | |
return true; | |
} | |
if (data < current.data) { | |
current = current.left; | |
} else { | |
current = current.right; | |
} | |
} | |
return false; | |
} | |
remove(data) { | |
const removeNode = function(node, data) { | |
if (node == null) { | |
return null; | |
} | |
if (data == node.data) { | |
// node has no children | |
if (node.left == null && node.right == null) { | |
return null; | |
} | |
// node has no left child | |
if (node.left == null) { | |
return node.right; | |
} | |
// node has no right child | |
if (node.right == null) { | |
return node.left; | |
} | |
// node has two children | |
var tempNode = node.right; | |
while (tempNode.left !== null) { | |
tempNode = tempNode.left; | |
} | |
node.data = tempNode.data; | |
node.right = removeNode(node.right, tempNode.data); | |
return node; | |
} else if (data < node.data) { | |
node.left = removeNode(node.left, data); | |
return node; | |
} else { | |
node.right = removeNode(node.right, data); | |
return node; | |
} | |
} | |
this.root = removeNode(this.root, data); | |
} | |
isBalanced() { | |
return (this.findMinHeight() >= this.findMaxHeight() - 1) | |
} | |
findMinHeight(node = this.root) { | |
if (node == null) { | |
return -1; | |
}; | |
let left = this.findMinHeight(node.left); | |
let right = this.findMinHeight(node.right); | |
if (left < right) { | |
return left + 1; | |
} else { | |
return right + 1; | |
}; | |
} | |
findMaxHeight(node = this.root) { | |
if (node == null) { | |
return -1; | |
}; | |
let left = this.findMaxHeight(node.left); | |
let right = this.findMaxHeight(node.right); | |
if (left > right) { | |
return left + 1; | |
} else { | |
return right + 1; | |
}; | |
} | |
pathBetweenNodes(root, nodeA, nodeB) { | |
// Function to check if there is a path from root | |
// to the given node. It also populates | |
// 'arr' with the given path | |
const getPath = (node, path, target) => { | |
// if root is null | |
// there is no path | |
if (!node) | |
return false; | |
// push the node's value in 'arr' | |
path.push(node.data); | |
// if it is the required node | |
// return true | |
if (node.val == target) | |
return true; | |
// else check whether the required node lies | |
// in the left subtree or right subtree of | |
// the current node | |
if (getPath(node.left, path, target) || getPath(node.right, path, target)) | |
return true; | |
// required node does not lie either in the | |
// left or right subtree of the current node | |
// Thus, remove current node's value from | |
// 'arr'and then return false | |
path.pop(); | |
return false; | |
} | |
// intersection | |
let path1 = []; | |
let path2 = []; | |
getPath(root, path1, nodeA); | |
getPath(root, path2, nodeB); | |
let intersection = -1; | |
// Get intersection point | |
int i = 0, j = 0; | |
while (i != path1.length || j != path2.length { | |
// Keep moving forward until no intersection | |
// is found | |
if (i == j && path1[i] == path2[i] { | |
i++; | |
j++; | |
} | |
else { | |
intersection = j - 1; | |
break; | |
} | |
} | |
// Print the required path | |
for ( i = path1.size() - 1; i > intersection; i--) | |
System.out.print( path1.get(i) + " "); | |
for ( i = intersection; i < path2.size(); i++) | |
System.out.print( path2.get(i) + " "); | |
}, | |
rootToLeafPaths(root) { | |
if (!root) return null | |
let res = []; | |
const dfs = (node, path) => { | |
if (path == "") path = node.val.toString(); | |
else | |
path = `${path}->${node.val}` | |
if (node.left == null && node.right == null) { | |
res.push(path) | |
return; | |
} | |
dfs(node.left, path); | |
dfs(node.right, path); | |
} | |
dfs(root, "") | |
return res; | |
}, | |
inOrder() { | |
if (this.root == null) { | |
return null; | |
} else { | |
var result = new Array(); | |
function traverseInOrder(node) { | |
node.left && traverseInOrder(node.left); | |
result.push(node.data); | |
node.right && traverseInOrder(node.right); | |
} | |
traverseInOrder(this.root); | |
return result; | |
}; | |
} | |
preOrder() { | |
if (this.root == null) { | |
return null; | |
} else { | |
var result = new Array(); | |
function traversePreOrder(node) { | |
result.push(node.data); | |
node.left && traversePreOrder(node.left); | |
node.right && traversePreOrder(node.right); | |
}; | |
traversePreOrder(this.root); | |
return result; | |
}; | |
} | |
postOrder() { | |
if (this.root == null) { | |
return null; | |
} else { | |
var result = new Array(); | |
function traversePostOrder(node) { | |
node.left && traversePostOrder(node.left); | |
node.right && traversePostOrder(node.right); | |
result.push(node.data); | |
}; | |
traversePostOrder(this.root); | |
return result; | |
} | |
} | |
greaterSumTree() { | |
evaluateNode(null, root, 0); | |
return root; | |
var evaluateNode = function (parent, node, acc) { | |
let finalAcc = 0; | |
// Base case. We hit leaf nodes. | |
if (node.right == null && node.left == null) { | |
// Current node is a right child. | |
if (node.val > parent.val) | |
node.val += acc; | |
// Current node is a left child. | |
if (node.val < parent.val) | |
node.val += parent.val; | |
return node.val; | |
} | |
if (node.right != null) { | |
node.val += evaluateNode(node, node.right, acc);; | |
finalAcc = node.val; | |
} | |
if (node.left != null) { | |
finalAcc = evaluateNode(node, node.left, node.val);; | |
} | |
return finalAcc; | |
} | |
}, | |
levelOrder() { | |
let result = []; | |
let Q = []; | |
if (this.root != null) { | |
Q.push(this.root); | |
while(Q.length > 0) { | |
let node = Q.shift(); | |
result.push(node.data); | |
if (node.left != null) { | |
Q.push(node.left); | |
}; | |
if (node.right != null) { | |
Q.push(node.right); | |
}; | |
}; | |
return result; | |
} else { | |
return null; | |
}; | |
}; | |
} | |
const bst = new BST(); | |
bst.add(9); | |
bst.add(4); | |
bst.add(17); | |
bst.add(3); | |
bst.add(6); | |
bst.add(22); | |
bst.add(5); | |
bst.add(7); | |
bst.add(20); | |
console.log(bst.findMinHeight()); | |
console.log(bst.findMaxHeight()); | |
console.log(bst.isBalanced()); | |
bst.add(10); | |
console.log(bst.findMinHeight()); | |
console.log(bst.findMaxHeight()); | |
console.log(bst.isBalanced()); | |
console.log('inOrder: ' + bst.inOrder()); | |
console.log('preOrder: ' + bst.preOrder()); | |
console.log('postOrder: ' + bst.postOrder()); | |
console.log('levelOrder: ' + bst.levelOrder()); |
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