[C++] 백준 10866번 : 덱

https://www.acmicpc.net/problem/10866

#include <iostream>

#include <string>

#include <vector>

using namespace std;

class Deque {

public:

int length;

vector<int> d;

Deque() {

length = 0;

}

void push_front(int n) {

if (length != 0) {

d.push_back(d[length - 1]);

for (int i = d.size()-1; i > 0; i--) {

d[i] = d[i - 1];

}

d[0] = n;

}

else

d.push_back(n);

length++;

}

void push_back(int n) {

d.push_back(n);

length++;

}

void pop_back() {

if (length!=0) {

cout << d[length - 1] << "\n";

d.pop_back();

length--;

}

else

cout << "-1\n";

}

void pop_front() {

if (length != 0) {

cout << d[0] << "\n";

for (int i = 0; i < d.size()-1; i++)

d[i] = d[i+1];

d.pop_back();

length--;

}

else

cout << "-1\n";

}

void size() {

cout << length << "\n";

}

void empty() {

if (length == 0)

cout << "1\n";

else

cout << "0\n";

}

void front() {

if (length != 0)

cout << d[0] << "\n";

else

cout << "-1\n";;

}

void back() {

if (length != 0)

cout << d[length - 1] << "\n";

else

cout << "-1\n";;

}

};

int main() {

int tc;

cin >> tc;

Deque k;

for (int i = 0; i < tc; i++) {

string input;

cin >> input;

int tmp;

if (input == "push_front") {

cin >> tmp;

k.push_front(tmp);

}

else if (input == "push_back") {

cin >> tmp;

k.push_back(tmp);

}

else if (input == "pop_front") {

k.pop_front();

}

else if (input == "pop_back") {

k.pop_back();

}

else if (input == "size") {

k.size();

}

else if (input == "empty") {

k.empty();

}

else if (input == "front") {

k.front();

}

else if (input == "back") {

k.back();

}

}

}