[백준-10845] 큐

<문제>

---

<Code>

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

int main(){
  int n;
  cin>>n;

  queue<int> q;
  int num;

  for(int i=0;i<n;i++){
    string str;
    cin>>str;

    if(str=="push"){
      int data;
      cin>>data;
      q.push(data);
    }else if(str=="pop"){
      if(q.size()!=0){
        num=q.front();
        q.pop();
      }else{
        num=-1;
      }
      cout<<num<<endl;

    }else if(str=="size"){
      cout<<q.size()<<endl;

    }else if(str=="empty"){
      if(q.size()==0){
        num=1;
      }else{
        num=0;
      }
      cout<<num<<endl;

    }else if(str=="front"){
      if(q.size()==0){
        num=-1;
      }else{
        num=q.front();
      }
      cout<<num<<endl;

    }else if(str=="back"){
      if(q.size()==0){
        num=-1;
      }else{
        num=q.back();
      }
      cout<<num<<endl;
    }
  }

  return 0;
}

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www.acmicpc.net/problem/10845

10845번: 큐