10866번: 덱

#include <iostream>

#include <deque>

#include <cstdio>

#include <cstring>

using namespace std;

int main()

{

deque<int> d;

char com[11];

int n;

cin >> n;

for (int i = 0, a; i < n; ++i)

{

scanf("%s", &com);

if (!strcmp(com, "push_front"))

{

cin >> a;

d.push_front(a);

}

else if (!strcmp(com, "push_back"))

{

cin >> a;

d.push_back(a);

}

else if (!strcmp(com, "pop_front"))

if (d.size() == 0)

cout << -1 << endl;

else

{

cout << d.front() << endl;

d.pop_front();

}

else if (!strcmp(com, "pop_back"))

if (d.size() == 0)

cout << -1 << endl;

else

{

cout << d.back() << endl;

d.pop_back();

}

else if (!strcmp(com, "size"))

cout << d.size() << endl;

else if (!strcmp(com, "empty"))

cout << d.empty() << endl;

else if (!strcmp(com, "front"))

if (d.size() == 0)

cout << -1 << endl;

else

cout << d.front() << endl;

else

if (d.size() == 0)

cout << -1 << endl;

else

cout << d.back() << endl;

}

}