10845) 큐 c++

문제 ) www.acmicpc.net/problem/10845

10845번: 큐

 

풀이 ) 

c++ STL을 이용해서 풀었다. 

 

코드 )

#include <iostream>
#include <queue>

using namespace std;

int N;
string cmd; 
queue<int> q;

int main(void)
{
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	cin >> N ;
	while(N--) {
		cin >> cmd;
		int num;
		if( cmd == "push" ){ 
			cin >> num;
			q.push(num);
		}
		else if( cmd == "pop" ) {
			if( !q.empty() ) {
				cout <<  q.front() << "\n";
				q.pop();
			}
			else cout << "-1\n";
		}
		else if( cmd == "size" ) {
			cout << q.size() << "\n";
		}
		else if( cmd == "empty" ) {
			if( !q.empty() ) cout << "0\n";
			else cout << "1\n";
		}
		else if( cmd == "front" ) {
			if( !q.empty() ) cout << q.front() << "\n";
			else cout << "-1\n";
		}
		else if( cmd == "back" ) {
			if(!q.empty()) cout << q.back() << "\n";
			else cout << "-1\n";
		}
	}
}