225. Implement Stack using Queues

//可以看一下leetcode的tutorial，它有的地方写的更简洁
class MyStack {
    // Push element x onto stack.
    int top;
    Queue<Integer> q=new LinkedList<Integer>();
    Queue<Integer> tmp=new LinkedList<Integer>();
    public void push(int x) {
        q.offer(x);
        top=x;
        
    }

    // Removes the element on top of the stack.
    public void pop() {
    if(q.isEmpty())
    return ;
    while(q.size()!=1){
        tmp.offer(q.poll());
        
    }
    q.poll();
    while(!tmp.isEmpty()){
    if(tmp.size()==1)
    {top=tmp.poll();
    q.offer(top);
    }
    else
    q.offer(tmp.poll());
    
    }
    }

    // Get the top element.
    public int top() {
        return top;
        
    }

    // Return whether the stack is empty.
    public boolean empty() {
        if(q.isEmpty())
        return true;
        else 
        return false;
        
    }
}
//pop地方写的更简洁
class MyStack {
    // Push element x onto stack.
    int top;
    Queue<Integer> q=new LinkedList<Integer>();
    Queue<Integer> tmp=new LinkedList<Integer>();
    public void push(int x) {
        q.offer(x);
        top=x;
        
    }

    // Removes the element on top of the stack.
    public void pop() {
    if(q.isEmpty())
    return ;
    while(q.size()!=1){
        top=q.poll();
        tmp.offer(top);
        
    }
    q.poll();
    Queue<Integer> trans=q;
    q=tmp;
    tmp=trans;
    }

    // Get the top element.
    public int top() {
        return top;
        
    }

    // Return whether the stack is empty.
    public boolean empty() {
        if(q.isEmpty())
        return true;
        else 
        return false;
        
    }
}