[백준/BOJ] 백준 18258번 : 큐 2

https://www.acmicpc.net/problem/18258

18258번: 큐 2

큐를 사용해서 문제를 해결했다.

 

코드

#include <iostream>
#include <algorithm>
#include <string>
#include <queue>
using namespace std;

int n;

int main()
{
	cin.tie(NULL);
	ios_base::sync_with_stdio(false);

	queue<int> q;
	string command;
	int input;

	cin >> n;

	for (int i = 0; i < n; i++)
	{
		cin >> command;

		if (command == "push")
		{
			cin >> input;
			q.push(input);
		}

		else if (command == "pop")
		{
			if (q.empty()) //큐가 비어있을떄
				cout << -1 << "\n";

			else
			{
				cout << q.front() << "\n";
				q.pop();
			}
		}

		else if (command == "size")
		{
			cout << q.size() << "\n";
		}

		else if (command == "empty")
		{
			if (q.empty()) //큐가 비어 있을때
				cout << 1 << "\n";
			else
				cout << 0 << "\n";
		}

		else if (command == "front")
		{
			if (q.empty()) //큐가 비어 있을때
				cout << -1 << "\n";
			else
				cout << q.front() << "\n";
		}

		else if (command == "back")
		{
			if (q.empty()) //큐가 비어 있을때
				cout << -1 << "\n";
			else
				cout << q.back() << "\n";
		}
	}

	return 0;
}