00_DesignOverview.cpp

/*
================================================================================
                    DESIGN DATA STRUCTURES - OVERVIEW
================================================================================

Design problems test your ability to:
1. Choose appropriate data structures
2. Achieve required time/space complexity
3. Handle edge cases
4. Write clean, maintainable code

Key Combinations:
- HashMap + Doubly Linked List → LRU Cache, LFU Cache
- HashMap + Array → Insert Delete GetRandom O(1)
- HashMap + Heap → Design Twitter, Top K
- Stack of Stacks → Min Stack
- Two Data Structures → Queue from Stacks

================================================================================
                           COMMON PATTERNS
================================================================================

1. CACHE DESIGNS
   ─────────────
   LRU, LFU, TTL-based caches
   Key: HashMap for O(1) access + ordering structure
   
2. RANDOM ACCESS IN O(1)
   ──────────────────────
   Insert, Delete, GetRandom all O(1)
   Key: Array + HashMap (swap with last on delete)
   
3. ITERATOR PATTERNS
   ──────────────────
   Flatten structures, peek ahead, filter
   Key: Stack for DFS-like iteration
   
4. TIME-BASED STRUCTURES
   ──────────────────────
   Versioned data, time-range queries
   Key: Binary search on timestamps
   
5. STREAM PROCESSING
   ──────────────────
   Moving average, rate limiter, hit counter
   Key: Queue with sliding window

================================================================================
                           FILE ORGANIZATION
================================================================================

01_CacheDesigns.cpp         - LRU, LFU, TTL Cache
02_HashMapDesigns.cpp       - HashMap, HashSet, RandomizedSet
03_StackQueueDesigns.cpp    - Min Stack, Queue from Stacks
04_IteratorPatterns.cpp     - Flatten, Peek, Zigzag iterators
05_TimeBasedDesigns.cpp     - Snapshot Array, Time Key-Value Store
06_AdvancedDesigns.cpp      - Twitter, Browser History, Skiplist

================================================================================
*/

#include <bits/stdc++.h>
using namespace std;

int main() {
    cout << "=== Design Data Structures ===" << endl;
    cout << "See individual files for implementations." << endl;
    return 0;
}