[18258] 백준 : 큐2(C++)

 

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2019/11/20 - [알고리즘 공부] - [10845] 백준 알고리즘 : 큐(C++)

[10845] 백준 알고리즘 : 큐(C++)

 

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

int main() {
	// 입출력 속도 개선
	cin.tie(NULL);
	ios_base::sync_with_stdio(false);

	int N = 0;
	cin >> N;

	queue<int> q;
	string str;
	for (int i = 0; i < N; i++)
	{
		cin >> str;

		if (str.compare("push") == 0)
		{
			int a;
			cin >> a;
			q.push(a);
		}
		else if (str.compare("pop") == 0)
		{
			if (q.empty())
				cout << -1 << "\n";
			else
			{
				cout << q.front() << "\n";
				q.pop();
			}
		}
		else if (str.compare("size") == 0)
		{
			cout << q.size() << "\n";
		}
		else if (str.compare("empty") == 0)
		{
			if (q.empty()) cout << 1 << "\n";
			else cout << 0 << "\n";
		}
		else if (str.compare("front") == 0)
		{
			if (q.empty())
				cout << -1 << "\n";
			else
				cout << q.front() << "\n";
		}
		else if (str.compare("back") == 0)
		{
			if (q.empty())
				cout << -1 << "\n";
			else
				cout << q.back() << "\n";
		}
	}
}