LeetCode题目：用栈实现队列

我就是我 2021-12-15 07:41 278阅读 0赞

## LeetCode题目：用栈实现队列 ##

**具体原理：**

> 首先用两个栈模拟队列，分别为输入栈InputStack和输出栈OutputStack。  
> \-push：InputStack栈添加数据  
> \-pop：把InputStack栈的数据拷贝给OutputStack栈。然后对OutputStack栈 执行pop 操作。完成之后将数据重新拷贝给InputStack，OutputStack清空  
> \-top：同pop理，但OutputStack栈执行top操作。 流程图如下：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1VwX2p1bmlvcg_size_16_color_FFFFFF_t_70]

#include<stack>
    using namespace std;
    class MyQueue {
    public:
    	/** Initialize your data structure here. */
    	MyQueue() {}
    	/** Push element x to the back of queue. */
    	void push(int x) {
    		InputStack.push(x);
    	}
    	/** Removes the element from in front of queue and returns that element. */
    	int pop() {
    		while (!InputStack.empty())
    		{
    			OutputStack.push(InputStack.top());
    			InputStack.pop();
    		}
    		int top = OutputStack.top();
    		OutputStack.pop();
    		while (!OutputStack.empty())
    		{
    			InputStack.push(OutputStack.top());
    			OutputStack.pop();
    		}
    		return top;
    	}
    	/** Get the front element. */
    	int peek() {
    		while (!InputStack.empty())
    		{
    			OutputStack.push(InputStack.top());
    			InputStack.pop();
    		}
    		int top = OutputStack.top();
    		while (!OutputStack.empty())
    		{
    			InputStack.push(OutputStack.top());
    			OutputStack.pop();
    		}
    		return top;
    	}
    	/** Returns whether the queue is empty. */
    	bool empty() {
    		if (OutputStack.empty() && InputStack.empty())
    			return true;
    		return false;
    	}
    private:
    	stack<int> InputStack;
    	stack<int> OutputStack;
    };

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1VwX2p1bmlvcg_size_16_color_FFFFFF_t_70]: /images/20211214/3cb47002627441d0adb7384050fcda43.png