Double-Ended Kingdom: Deque Operations

📋 OBJECTIVE

Master the Double-Ended Queue (Deque)! Insert and remove from BOTH ends - the ultimate flexibility!

📝 DEQUE OPERATIONS

// Double-Ended Queue
interface Deque {
  addFirst(x)    // Add to front
  addLast(x)     // Add to back
  removeFirst() // Remove front
  removeLast()  // Remove back
  getFirst()    // Peek front
  getLast()     // Peek back
}

// All operations O(1)!

💡 USE CASES

• Sliding window problems
• Palindrome checking
• Undo/Redo stacks
• Work stealing queues
• Browser history

👑 THE ROYAL DEQUE Insert from both ends!

FRONT

→ add ← remove

👑 Empty Deque - Add elements!

BACK

add ← remove →

- First (Front)

0 Size

- Last (Back)

👑 DOUBLE-ENDED KINGDOM

Success!