PATTERNS

• Fast & Slow Pointer
• Sliding Window
• Two Pointer
• Prefix Sum
• Kadane Algorithm
• Monotonic Stack / Queue
• Binary Search
• Binary Search on Answer
• Divide and Conquer
• Backtracking
• Backtracking – Subsets
• Recursion
• Dynamic Programming
• Greedy
• Breadth-First Search (BFS)
• Depth-First Search (DFS)
• Topological Sort
• Union Find (DSU)
• Heap / Priority Queue
• Trie (Prefix Tree)
• Dijkstra (Shortest Path)

Java Data Structures

• Array
• ArrayList
• LinkedList
• HashMap
• HashSet
• Tree
• TreeMap
• TreeSet
• Stack
• Queue
• Priority Queue
• ArrayDeque
• Graph (BFS + DFS)