Algorithmic Coding Challenges

Given a function `fn` and a time in milliseconds `t`, return a **debounced** version of that function. A **debounced** function is a function whose e...

Given the `head` of a singly linked list, reverse the list, and return the reversed list. ### Example 1 **Input:** head = [1,2,3,4,5] **Output:** [5,...

Given an array of integers `nums` and an integer `target`, return indices of the two numbers such that they add up to `target`. You may assume that e...

Develop a custom hook `useCounter` that supports increments, decrements, and optional reset bounds.

Create an EventEmitter class that supports registering listeners, emitting events, and removing listeners. Methods required: - on() - emit() - off()

Create a function that creates a deep copy of an object without sharing references with the original object. The cloned object should work with neste...

Implement a utility function that converts a callback-based function into a Promise-based function. The returned function should resolve successful r...

Implement a throttle utility that limits how frequently a function can execute. The function should execute immediately and ignore repeated calls unt...

Given a nested array, flatten it into a single-level array. The function should support multiple levels of nesting. Example: Input: [1,[2,[3,[4]]]] ...

Create a function that groups array elements based on a given key or callback function. Example: Input: [{age:20},{age:30},{age:20}] Output: {20:[......

Create a curry function that transforms a function with multiple arguments into a sequence of functions that each accept fewer arguments. Example: In...

Create a simplified version of JSON.stringify. Convert JavaScript objects and arrays into JSON formatted strings.

Implement a memoize function that stores previous function results and returns cached values for repeated inputs. This improves performance by avoidi...

Implement your own version of JavaScript Array.map without using the built-in map method. The function should accept a callback and return a new tran...

Flatten a nested array up to a given depth.

Implement your own version of Promise.all. It should take an array of promises and return a single promise that resolves when all input promises resol...

Implement Promise.race that resolves or rejects as soon as one promise settles.

Return a new array with duplicate values removed.

Create a function that reverses the order of arguments passed to a function.

Design and implement an LRU (Least Recently Used) cache.

Implement a pipeline function that executes functions left to right.

Split an array into chunks of given size.

Implement a compose function that combines multiple functions from right to left.

Check if two values are deeply equal (objects, arrays, primitives).

Create a search component that filters a list of items based on user input.

Create an infinite scrolling list that loads more data when the user reaches the bottom.

Implement drag and drop functionality to reorder list items.

Create a small state management solution using React concepts. Features: - Store state - Update state - Subscribe components

Create a React Todo component that allows users to add, delete, and mark tasks as completed. Requirements: - Add new todos - Remove todos - Toggle co...

Build a reusable Modal component using React. Features: - Open and close modal - Handle outside click - Render children content

Create a React error boundary that catches component errors and displays fallback UI.

Create a reusable pagination component that displays items page by page.

Create a search input that delays API calls until the user stops typing.

Implement a custom React hook that fetches API data and manages loading and error states.

Given intervals, merge all overlapping intervals.

Return the k most frequent elements in an array.

Return array where each element is product of all other elements except itself.

Rotate an array to the right by k steps.

Reverse a string using two pointers approach.

Find two numbers in a sorted array that add up to target.

Return all elements of a matrix in spiral order.

Search target in a sorted 2D matrix.

You are given an array where each element is price of a stock on a day. Find maximum profit by choosing a single buy and sell day.

Find minimum element in rotated sorted array using binary search.

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. A string is valid if open brac...

Implement binary search to find target in sorted array.

Check if two strings are anagrams of each other.

Detect if a linked list has a cycle.

Count number of ways to reach nth stair.

Find index of first non-repeating character in a string.

Find the contiguous subarray with the largest sum.

Find the length of the longest substring without repeating characters.

Find two lines that together with x-axis forms container with max water.

Create a countdown timer that decreases every second using useEffect and useState. It should stop at zero and clean up properly.

Build a theme toggle button that switches between light and dark mode using React state.

Create a form with validation for email, password strength, and required fields.

Implement authentication state management using React Context API.

Optimize a large list filtering operation using useMemo to avoid unnecessary recalculations.

Use useCallback to prevent unnecessary re-renders of child components when passing event handlers.

Create a React Error Boundary that catches runtime errors and displays fallback UI.

Create a nested component structure where clicking a child button should not trigger parent click events. Demonstrate proper event handling using stop...

Build a custom hook that stores and returns the previous state value.

Create a multi-step form with next/back navigation and state persistence across steps.

Filter a list of items based on user input search query.

Build a list that loads more data when user scrolls to bottom.

Build a todo list optimized using React.memo and useCallback to prevent unnecessary re-renders.

Build a reusable hook to fetch API data with loading and error states.

Create a reusable modal with open/close functionality and overlay click handling.

Build an input component that toggles between controlled and uncontrolled modes.