Arrays & Hashing

Master array manipulation, hash maps, two-pointer techniques, and sliding window patterns — the most common interview topics at top tech companies.

23 exercises

mediumTypeScript

Todo List State Management

# Todo List Component Implement a `TodoList` class that manages todo items with full CRUD functionality. Each todo shou...

typescriptstate-managementcrud+5

easyPython

URL Shortener with Base62 Encoding

Build a URL shortener class that can encode long URLs into short codes and decode them back. Implement a `URLShortener`...

hash-map

mediumPython

Consistent Hashing Ring

# Consistent Hashing Ring Implement a consistent hashing ring data structure that distributes keys across nodes while m...

hashing

mediumTypeScript

Rate Limiter Middleware

Build a rate limiter middleware that tracks requests per IP address and enforces a limit of 10 requests per minute. ##...

mediumPython

Minimum Jumps to Reach End

# Minimum Jumps to Reach End Implement a function that finds the minimum number of jumps needed to reach the last index...

arrays

hardPython

Sliding Window Maximum

Implement a function that finds the maximum value in each sliding window of size k across an array. Given an array of i...

sliding-window

hardPython

Median of Two Sorted Arrays

Find the median of two sorted arrays in O(log(m+n)) time complexity. Implement a function that takes two sorted arrays...

binary-search

mediumPython

Binary Search for First and Last Position

# Find First and Last Position in Sorted Array Implement a function that finds the first and last position of a target...

binary-search

mediumPython

Find Kth Largest Element

Implement a function that finds the kth largest element in an unsorted array without sorting the entire array. Your fun...

algorithms

easyPython

Search in Rotated Sorted Array

Implement a function that searches for a target value in a rotated sorted array in O(log n) time complexity. A rotated...

binary-search

easyPython

Merge Sorted Arrays In-Place

Write a function `merge_sorted_arrays(arr1, arr2)` that merges two sorted arrays into one sorted array. **Examples:** `...

arrays

easyPython

Binary Search Implementation

Implement a binary search function that finds the index of a target value in a sorted array. **Function signature:** `b...

algorithms

Page 1 of 2Next