题解 | #用两个栈实现队列#第35道题,100道还远吗?
用两个栈实现队列
https://www.nowcoder.com/practice/54275ddae22f475981afa2244dd448c6
import java.util.*; import java.util.Stack; public class Solution { Stack<Integer> stack1 = new Stack<Integer>(); Stack<Integer> stack2 = new Stack<Integer>(); public void push(int node) { while(stack2.size()>0) {stack1.push(stack2.pop());}//这里很重要,stack2的还得还回去 stack1.push(node); } public int pop() { if(stack1.size()==0){return stack2.pop();} else{ while(stack1.size()>0){ stack2.push(stack1.pop()); } return stack2.pop(); } } }