用两个栈实现队列

import java.util.Stack;

public class Solution {
Stack<Integer> stack1 = new Stack<Integer>();
Stack<Integer> stack2 = new Stack<Integer>();

public void push(int node) {
stack1.push(node);
}

public int pop() {
while(!stack1.empty()){
stack2.push(stack1.pop());
}
int val = stack2.pop();
while(!stack2.empty()){
stack1.push(stack2.pop());
}
return val;

}
}