package com.open.learncode.算法.java.leetcode.A1_栈与队列;
import com.open.learncode.算法.base.PrintUtils;
import java.util.Stack;
/**
题目:
用两个栈来实现一个队列，完成n次在队列尾部插入整数(push)和在队列头部删除整数(pop)的功能。
队列中的元素为int类型。保证操作合法，即保证pop操作时队列内已有元素。
<p>
数据范围：
n <= 1000
<p>
复杂度分析：
-
时间复杂度O(1)，空间复杂度O(n)
*/
public class JZ09_1_用两个栈实现队列 {public static void main(String[] args) {
// 测试示例
Solution solution = new Solution();
solution.push(1);
solution.push(2);
PrintUtils.getInstance().print(solution.pop());
PrintUtils.getInstance().print(solution.pop());
}private static class Solution {
private Stack<Integer> inStack = null;
private Stack<Integer> outStack = null;public Solution() { inStack = new Stack<Integer>(); outStack = new Stack<Integer>(); } public void push(int node) { inStack.push(node); } public int pop() { if (outStack.isEmpty()) { while (!inStack.isEmpty()) { outStack.push(inStack.pop()); } } return outStack.isEmpty() ? -1 : outStack.pop(); }}
}
