Data Structures & Algorithms (beginner to advanced)
• Arrays, Strings, Linked Lists, Stacks, Queues
• Trees, BSTs, Tries, Heaps, Hash Maps
• Graphs — BFS, DFS, Dijkstra, Topological Sort
• Recursion, Backtracking, Greedy, Dynamic Programming
• Sorting, searching, sliding window, two pointers, bit manipulation