Deque of infinite size
include <bits/stdc++.h>
using namespace std; using ll = long long;
int main() { iosbase::syncwith_stdio(0); cin.tie(0); string s; deque<int> dq; int x; while(cin >> s){ if(s == "exit"){ cout << "bye"; return 0; } if(s == "push_front"){ cin >> x; dq.push_front(x); cout << "ok"; } if(s == "push_back"){ cin >> x; dq.push_back(x); cout << "ok"; } if(s == "pop_front"){ if(dq.size() == 0) cout << "error"; else { cout << dq.front(); dq.pop_front(); } } if(s == "pop_back"){ if(dq.size() == 0) cout << "error"; else { cout << dq.back(); dq.pop_back(); } } if(s == "front"){ if(dq.size() == 0) cout << "error"; else { cout << dq.front(); } } if(s == "back"){ if(dq.size() == 0) cout << "error"; else { cout << dq.back(); } } if(s == "size"){ cout << dq.size(); } if(s == "clear"){ dq.clear(); cout << "ok"; } cout << endl; } }
include <iostream>
include <deque>
include <string>
using namespace std;
class MyDeque { protected: deque<int> dq;
public: void push_front(int x) { dq.push_front(x); cout << "ok" << endl; }
void push_back(int x) {
dq.push_back(x);
cout << "ok" << endl;
}
int pop_front() {
if (!dq.empty()) {
int value = dq.front();
dq.pop_front();
cout << value << endl;
return value;
} else {
cout << "error" << endl;
return -2000000000;
}
}
int pop_back() {
if (!dq.empty()) {
int value = dq.back();
dq.pop_back();
cout << value << endl;
return value;
} else {
cout << "error" << endl;
return -2000000000;
}
}
int front() {
if (!dq.empty()) {
cout << dq.front() << endl;
return dq.front();
} else {
cout << "error" << endl;
return -2000000000;
}
}
int back() {
if (!dq.empty()) {
cout << dq.back() << endl;
return dq.back();
} else {
cout << "error" << endl;
return -2000000000;
}
}
int size() {
cout << dq.size() << endl;
return dq.size();
}
void clear() {
dq.clear();
cout << "ok" << endl;
}
void exit() {
cout << "bye" << endl;
}
};
int main() { MyDeque deque;
string command;
int value;
while (cin >> command) {
if (command == "push_back") {
cin >> value;
deque.push_back(value);
} else if (command == "push_front") {
cin >> value;
deque.push_front(value);
} else if (command == "pop_back") {
deque.pop_back();
} else if (command == "pop_front") {
deque.pop_front();
} else if (command == "front") {
deque.front();
} else if (command == "back") {
deque.back();
} else if (command == "size") {
deque.size();
} else if (command == "clear") {
deque.clear();
} else if (command == "exit") {
deque.exit();
break;
}
}
return 0;
}