Daily TemperaturesTop K Frequent Elements (Heap)

Implement Queue Using Stacks

easy

Time: O(1) amortized

Space: O(n)

Implement a first-in-first-out (FIFO) queue using only two stacks.

Constraints

All calls are valid (pop/peek on non-empty queue).

Examples

Input: MyQueue q = new MyQueue(); q.Push(1); q.Push(2); q.Peek(); // 1 q.Pop(); // 1 q.Empty(); // false

Output: null