Queues operate on First-In, First-Out (FIFO) access order. Master level-order BFS tree traversals, double-ended queues (std::deque), and monotonic deques for sliding window maximum problems in C++.
FIFO Discipline: First elements added are processed first, ideal for BFS shortest path exploration.
Double-Ended Queue (std::deque): Allows O(1) push and pop at both head and tail ends.
Monotonic Deque: Evicts stale indices and smaller values to extract max/min in sliding windows in O(1).
Circular Buffer Queue: Implements bounded memory queues with fixed array wrap-around pointers.