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Count Unival Subtrees in a Binary Tree

A unival tree (short for "universal value tree") is a tree in which all nodes have the same value. Given…

2 months ago

Count Decoding Ways for Encoded Messages

Problem Statement (Asked By Facebook) Given the mapping a = 1, b = 2, ..., z = 26, and an…

2 months ago

Implement an XOR Linked List

An XOR-linked list is a memory-efficient version of a doubly linked list. Instead of each node storing separate next and…

2 months ago

Construct and Deconstruct a Pair

Problem Statement (Asked By Jane Street) The function cons(a, b) creates a pair of two elements. Implement two functions: car(pair):…

2 months ago

Find the Smallest Missing Positive Integer

Problem Statement (Asked By Stripe) You are given an array of integers. Your task is to find the smallest missing…

2 months ago

Serialize and Deserialize a Binary Tree

Given the root of a binary tree, create two functions: serialize(root) - Converts the binary tree into a string representation.…

2 months ago

Product of Array Except Self

Problem Statement (Asked By Uber) Given a list of integers, return a new list such that each element at index…

2 months ago

Two Sum: Check for Two Numbers with Sum K

Problem Statement (Asked By Google) Given a list of integers and a target number k, determine if there exist two…

2 months ago