184. Implement Queue using Stacks
EasyDesign
Implement a first in first out (FIFO) queue using only two stacks. The implemented queue should support all the functions of a normal queue (push, peek, pop, and empty). Implement the MyQueue class: - void push(int x) Pushes element x to the back of the queue. - int pop() Removes the element from the front of the queue and returns it. - int peek() Returns the element at the front of the queue. - boolean empty() Returns true if the queue is empty, false otherwise.
Examples
Input: ["MyQueue","push","push","peek","pop","empty"] [[],[1],[2],[],[],[]]
Output: [null,null,null,1,1,false]
Explanation: Queue operations: push 1, push 2, peek returns 1, pop returns 1, not empty.
Constraints
- 1 <= x <= 9
- At most 100 calls will be made to push, pop, peek, and empty.
- All the calls to pop and peek are valid.
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