225_Implement_stack_using_queues

// https://leetcode.com/problems/implement-stack-using-queues/

// My solution

class MyStack {
    //LinkedList<Integer> stack;
    LinkedList<Integer> q1;
    int top;
    /** Initialize your data structure here. */
    public MyStack() {
         //stack = new LinkedList<Integer>();
        q1 = new LinkedList<Integer>();
        top = -1;
    }
    
    /** Push element x onto stack. */
    public void push(int x) {
        // stack.add(x);
        // top++;
        q1.add(x);
    int sz = q1.size();
    while (sz > 1) {
        q1.add(q1.remove());
        sz--;
    }
    }
    
    /** Removes the element on top of the stack and returns that element. */
    public int pop() {
        // int tmp = top;
        // while(tmp!=0) {
        //     stack.add(stack.remove());
        //     tmp--;
        // }
        // top--;
        // // stack.remove();
        // return stack.remove();
        return q1.remove();
    }
    
    /** Get the top element. */
    public int top() {
        // int tmp = top;
        // while(tmp!=0) {
        //     stack.add(stack.remove());
        //     tmp--;
        // }
        // int peek = stack.remove();
        // stack.add(peek);
        // return peek;
        return q1.peek();
    }
    
    /** Returns whether the stack is empty. */
    public boolean empty() {
        // if(top==-1)
        //    return true;
        // else
        //     return false;
        return q1.isEmpty();
    }
}

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