Subtree - Amazon Top Interview Questions
Problem Statement :
You are given two binary trees root, and target. Return whether target is a subtree of root — that is, whether there's a node in root that is identically same in values and structure as root including all of its descendants. Example 1 Input root = [1, [2, null, null], [3, [4, [6, null, null], null], [5, null, [7, null, null]]]] target = [3, [4, [6, null, null], null], [5, null, [7, null, null]]] Output True Example 2 Input root = [1, [2, null, null], [3, [4, [6, null, null], null], [5, null, [7, null, null]]]] target = [3, null, [5, null, null]] Output False Example 3 Input root = [0, null, [5, [1, null, null], null]] target = [0, null, [5, [1, null, null], null]] Output True
Solution :
Solution in C++ :
/**
* class Tree {
* public:
* int val;
* Tree *left;
* Tree *right;
* };
*/
bool flag;
bool identical(Tree* root, Tree* target) {
if (!root && !target) return true;
if (!root || !target) return false;
if (root->val != target->val) return false;
return identical(root->left, target->left) && identical(root->right, target->right);
}
void traverse(Tree* root, Tree* target) {
if (!root) return;
if (root->val == target->val) {
flag = flag | identical(root, target);
}
traverse(root->left, target);
traverse(root->right, target);
}
bool solve(Tree* root, Tree* target) {
flag = false;
if (!target) return true;
traverse(root, target);
return flag;
}
Solution in Python :
# class Tree:
# def __init__(self, val, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def merkleHash(self, root):
if not root:
return "-"
leftHash = self.merkleHash(root.left)
rightHash = self.merkleHash(root.right)
root.merkle = leftHash + ":{}:".format(root.val) + rightHash
return root.merkle
def solve(self, root, target):
self.merkleHash(root)
self.merkleHash(target)
def dfs(cur):
if not cur:
return False
return cur.merkle == target.merkle or dfs(cur.left) or dfs(cur.right)
return dfs(root)
View More Similar Problems
Tree: Level Order Traversal
Given a pointer to the root of a binary tree, you need to print the level order traversal of this tree. In level-order traversal, nodes are visited level by level from left to right. Complete the function levelOrder and print the values in a single line separated by a space. For example: 1 \ 2 \ 5 / \ 3 6 \ 4 F
View Solution →Binary Search Tree : Insertion
You are given a pointer to the root of a binary search tree and values to be inserted into the tree. Insert the values into their appropriate position in the binary search tree and return the root of the updated binary tree. You just have to complete the function. Input Format You are given a function, Node * insert (Node * root ,int data) { } Constraints No. of nodes in the tree <
View Solution →Tree: Huffman Decoding
Huffman coding assigns variable length codewords to fixed length input characters based on their frequencies. More frequent characters are assigned shorter codewords and less frequent characters are assigned longer codewords. All edges along the path to a character contain a code digit. If they are on the left side of the tree, they will be a 0 (zero). If on the right, they'll be a 1 (one). Only t
View Solution →Binary Search Tree : Lowest Common Ancestor
You are given pointer to the root of the binary search tree and two values v1 and v2. You need to return the lowest common ancestor (LCA) of v1 and v2 in the binary search tree. In the diagram above, the lowest common ancestor of the nodes 4 and 6 is the node 3. Node 3 is the lowest node which has nodes and as descendants. Function Description Complete the function lca in the editor b
View Solution →Swap Nodes [Algo]
A binary tree is a tree which is characterized by one of the following properties: It can be empty (null). It contains a root node only. It contains a root node with a left subtree, a right subtree, or both. These subtrees are also binary trees. In-order traversal is performed as Traverse the left subtree. Visit root. Traverse the right subtree. For this in-order traversal, start from
View Solution →Kitty's Calculations on a Tree
Kitty has a tree, T , consisting of n nodes where each node is uniquely labeled from 1 to n . Her friend Alex gave her q sets, where each set contains k distinct nodes. Kitty needs to calculate the following expression on each set: where: { u ,v } denotes an unordered pair of nodes belonging to the set. dist(u , v) denotes the number of edges on the unique (shortest) path between nodes a
View Solution →