(28279) 덱 2

https://www.acmicpc.net/problem/28279

단계별로 풀어보기

16단계(스택, 큐, 덱 1) 9번째

 

 

 

#include <iostream>
#include <queue>
using namespace std;

int main() 
{
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  
  deque<int> dq;
  int n;
  
  cin >> n;
  
  while(n--){
    int q;
    
    cin >> q;
    
    if(q==1){
      int x;
      
      cin >> x;
      
      dq.push_front(x);
    }else if(q==2){
      int x;
      
      cin >> x;
      
      dq.push_back(x);
    }else if(q==3){
      if(!dq.empty()){
        cout << dq.front() << "\n";
        dq.pop_front();
      }else{
        cout << "-1\n";
      }
    }else if(q==4){
      if(!dq.empty()){
        cout << dq.back() << "\n";
        dq.pop_back();
      }else{
        cout << "-1\n";
      }
    }else if(q==5){
      cout << dq.size() << "\n";
    }else if(q==6){
      cout << dq.empty() << "\n";
    }else if(q==7){
      if(!dq.empty()){
        cout << dq.front() << "\n";
      }else{
        cout << "-1\n";
      }
    }else if(q==8){
      if(!dq.empty()){
        cout << dq.back() << "\n";
      }else{
        cout << "-1\n";
      }
    }
  }
  
  return 0;
}