[백준 알고리즘/C++/큐] 18258 큐2

 

 

 

기본적인 큐 기능을 구현하는 문제

 

 

#include <iostream>
#include <deque>
using namespace std;
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
 
    int n, input;
    string str;
    deque<int> que;
    cin >> n;
 
    while (n--) {
        cin >> str;
 
        if (str == "push") {
            cin >> input;
            que.push_back(input);
        }
        else if (str == "pop") {
            if (que.empty()) {
                cout << -1 << "\n";
                continue;
            }
            cout << que.front() << "\n";
            que.pop_front();
        }
        else if (str == "size")
            cout << que.size() << "\n";
        else if (str == "empty")
            cout << que.empty() << "\n";
        else if (str == "front") {
            if (que.empty()) {
                cout << -1 << "\n";
                continue;
            }
            cout << que.front() << "\n";
        }
        else if (str == "back") {
            if (que.empty()) {
                cout << -1 << "\n";
                continue;
            }
            cout << que.back() << "\n";
        }
    }
}

 

왜.. 덱을 썼을까? queue로 하면 됨