Puzzles
You watched it. Now prove it— play each algorithm's strategy by hand. Solving locks the idea into memory in a way watching never can.
Guess my number
Apply Binary Search
Learn Binary Search first →
🔒 LockedClose the gap
Apply Two Pointers
Learn Two Pointers first →
🔒 LockedSpread the search
Apply BFS
Learn Breadth-First Search first →
🔒 LockedBeat the scan
Apply Hashing
Learn Hashing (Hash Set) first →
🔒 LockedGo deep
Apply DFS
Learn Depth-First Search first →
🔒 LockedNext out
Apply Stack & Queue
Learn Stack & Queue first →
🔒 LockedFind its place
Apply Insertion Sort
Learn Insertion Sort first →
🔒 LockedScan it
Apply Linear Search
Learn Linear Search first →
🔒 LockedFind the box
Apply Arrays
Learn What is an Array? first →
🔒 LockedSpot the break
Apply Sorted Order
Learn What is Sorted? first →
🔒 LockedBubble it up
Apply Bubble Sort
Learn Bubble Sort first →
🔒 LockedMerge them
Apply Merge Sort
Learn Merge Sort first →
🔒 LockedUnwind it
Apply Recursion
Learn Recursion: Factorial first →
🔒 LockedFollow the links
Apply Linked List
Learn Linked List Traversal first →
🔒 LockedWalk in order
Apply Tree Traversal
Learn Tree Traversal (In-order) first →
🔒 LockedFill the steps
Apply Climbing Stairs
Learn DP: Climbing Stairs first →