[백준] 큐(10845번) - C++

문제

입력

출력

소스 코드

#include <iostream>
#include <queue>

using namespace std;

int main() {
	int n; cin >> n;
	queue<int> q;
	for(int i=0;i<n;i++) {
		string command; cin >> command;
		if(command == "push") {
			int num; cin >> num;
			q.push(num);
		}
		else if(command == "pop") {
			if(q.empty()) 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()) cout << 1 <<"\n";
			else cout << 0 << "\n";
		}
		else if(command == "front") {
			if(q.empty()) cout << -1 << "\n";
			else {
				cout << q.front() << "\n";
			}
		}
		else {
			if(q.empty()) cout << -1 << "\n";
			else {
				cout << q.back() << "\n";
			}
		}
	}
	return 0;
}