Queue Coding Challenges

Return the front element of a queue without removing it. Teaches the peek operation and handling the empty queue edge case.

Return the number of elements in a queue. Teaches the size operation for array-based queues and the concept of tracking element counts.

Clear all elements from a queue by returning an empty array. Covers the clear operation for both array-based and linked-list queue implementations.

Push (enqueue) a new value to the back of a queue array. Teaches the FIFO principle and the fundamental enqueue operation with O(1) amortized append.

Check whether a queue is empty before performing operations. Teaches defensive programming and the O(1) emptiness check pattern for collections.

Reverse the order of elements in a deque. Teaches the two-pointer swap technique and its application to double-ended queue reversal.

Rotate elements to the left by k positions (simulating deque rotation).

Check whether a deque is a palindrome by comparing front and back elements. Teaches symmetric comparison and deque-based palindrome checking.

Initialize a circular queue of size n with sequential values.

Return the front element of a deque without removing it. Teaches peek operations and the role of deque front in BFS and sliding window algorithms.

Find the kth smallest element using sorted array (min-priority queue simulation).

Find the kth largest element in an array.

Return the minimum element from a min-heap priority queue without removing it. Teaches O(1) peek at heap root and the min-heap invariant.

Sum the k largest elements (simulating priority queue polling).

Return the maximum element from a max-heap priority queue without removing it. Teaches O(1) peek at heap root and the max-heap invariant.