// @Title: 用栈实现队列 (Implement Queue using Stacks)
// @Author: qisiii
// @Date: 2024-01-02 22:07:30
// @Runtime: 0 ms
// @Memory: 40.3 MB
// @comment: 
// @flag: 
class MyQueue {

    Stack<Integer> push=new Stack();
    Stack<Integer> pop=new Stack();
    public MyQueue() {

    }

    public void push(int x) {
        while (!push.isEmpty()){
            Integer obj = push.pop();
            pop.push(obj);
        }
        push.push(x);
        while (!pop.isEmpty()){
            push.push(pop.pop());
        }
    }

    public int pop() {
        return push.pop();
    }

    public int peek() {
        return push.peek();
    }

    public boolean empty() {
        return push.isEmpty();
    }
}

/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue obj = new MyQueue();
 * obj.push(x);
 * int param_2 = obj.pop();
 * int param_3 = obj.peek();
 * boolean param_4 = obj.empty();
 */

// @Title: 用栈实现队列 (Implement Queue using Stacks)
// @Author: qisiii
// @Date: 2024-09-14 11:33:18
// @Runtime: 0 ms
// @Memory: 40.3 MB
// @comment: 
// @flag: 
class MyQueue {
    private Stack<Integer> popStack = new Stack();
    private Stack<Integer> pushStack = new Stack();

    public MyQueue() {

    }

    public void push(int x) {
        pushStack.push(x);
    }

    public int pop() {
        if (popStack.isEmpty()) {
            while (!pushStack.isEmpty()) {
                popStack.push(pushStack.pop());
            }
        }
        return popStack.pop();
    }

    public int peek() {
        if (popStack.isEmpty()) {
            while (!pushStack.isEmpty()) {
                popStack.push(pushStack.pop());
            }
        }
        return popStack.peek();
    }

    public boolean empty() {
        return pushStack.isEmpty() && popStack.isEmpty();
    }
}

/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue obj = new MyQueue();
 * obj.push(x);
 * int param_2 = obj.pop();
 * int param_3 = obj.peek();
 * boolean param_4 = obj.empty();
 */

// @Title: 用栈实现队列 (Implement Queue using Stacks)
// @Author: qisiii
// @Date: 2022-02-28 16:23:07
// @Runtime: 1 ms
// @Memory: 38.8 MB
// @comment: 
// @flag: 
class MyQueue {
    private Stack<Integer> pushStack=new Stack();
private Stack<Integer> popStack=new Stack();
    public MyQueue() {

    }
    
    public void push(int x) {
        pushStack.push(Integer.valueOf(x));
    }
    
    public int pop() {
        if(popStack.isEmpty()){
           while(!pushStack.isEmpty()){
                Integer v= pushStack.pop();
                popStack.push(v);
            }
        }
        if(popStack.isEmpty()){
            return -1;
        }
        return popStack.pop();
    }
    
    public int peek() {
        if(popStack.isEmpty()){
            while(!pushStack.isEmpty()){
                Integer v= pushStack.pop();
                popStack.push(v);
            }
        }
        return popStack.peek();
    }
    
    public boolean empty() {
        return pushStack.isEmpty()&&popStack.isEmpty();
    }
}

/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue obj = new MyQueue();
 * obj.push(x);
 * int param_2 = obj.pop();
 * int param_3 = obj.peek();
 * boolean param_4 = obj.empty();
 */

// @Title: 用栈实现队列 (Implement Queue using Stacks)
// @Author: qisiii
// @Date: 2024-08-13 15:19:28
// @Runtime: 0 ms
// @Memory: 40.3 MB
// @comment: 
// @flag: 
class MyQueue {
    private Stack<Integer> push=new Stack<>();
    private Stack<Integer> pop=new Stack<>();
    public MyQueue() {

    }
    
    public void push(int x) {
        push.push(x);
    }
    
    public int pop() {
        if(empty()){
            return -1;
        }
        if(pop.isEmpty()){
            while(!push.isEmpty()){
                pop.push(push.pop());
            }
        }
        return pop.pop();
    }
    
    public int peek() {
        if(empty()){
            return -1;
        }
        if(pop.isEmpty()){
            while(!push.isEmpty()){
                pop.push(push.pop());
            }
        }
        return pop.peek();
    }
    
    public boolean empty() {
        return push.isEmpty()&&pop.isEmpty();
    }
}

/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue obj = new MyQueue();
 * obj.push(x);
 * int param_2 = obj.pop();
 * int param_3 = obj.peek();
 * boolean param_4 = obj.empty();
 */