fork download
copy 
  1. #include<bits/stdc++.h>
  2. #include<vector>
  3. using namespace std;
  4.  
  5. int main(){
  6.     int n,d;
  7.     cin>>n;
  8.     int nc=n;
  9.     vector<int> vi;
  10.     int flag=0,f1=0;
  11.     while(n!=0)
  12.     {
  13.         d=n%10;
  14.         vi.push_back(d);
  15.         n/=10;
  16.     }
  17.     int i,sum=0;
  18.     for(i=0;i<vi.size();i++){
  19.         sum+=vi[i];
  20.     }
  21.     int rm=sum%3;
  22.     if(rm==0){
  23.         cout<<nc;
  24.         return 0;
  25.     }
  26.     else if(rm==1){
  27.         for(i=0;i<vi.size();i++){
  28.             if(vi[i]%3==1&&vi.size()>1){
  29.                 vi.erase(vi.begin()+i);
  30.                 flag=1;
  31.                 break;
  32.             }
  33.         }
  34.     }
  35.     else{
  36.         for(i=0;i<vi.size();i++){
  37.             if(vi[i]%3==2&&vi.size()>1){
  38.                 vi.erase(vi.begin()+i);
  39.                 flag=1;
  40.                 break;
  41.             }
  42.         }
  43.         if(flag==0){
  44.                 //cout<<"here";
  45.             for(i=0;i<vi.size();i++){
  46.                     if(f1==0){
  47.             if(vi[i]%3==1&&vi.size()>1){
  48.                 vi.erase(vi.begin()+i);
  49.                 f1=1;
  50.             }
  51.                     }
  52.                     else{
  53.  
  54.                         if(vi[i]%3==1&&vi.size()>1){
  55.                 vi.erase(vi.begin()+i);
  56.                 flag=1;
  57.                 break;
  58.             }
  59.                     }
  60.         }
  61.         }
  62.     }
  63.     if(flag==0)
  64.         cout<<-1;
  65.     else{
  66.         for(i=vi.size()-1;i>=0;i--){
  67.              if(vi.size()==1)
  68.             break;
  69.             if(vi[i]==0)
  70.                 vi.erase(vi.begin()+i);
  71.             else break;
  72.         }
  73.         for(i=vi.size()-1;i>=0;i--){
  74.                 cout<<vi[i];
  75.         }
  76.     }
  77.     return 0;
  78. }
  79.  
Success #stdin #stdout 0s 15240KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
-1
https://ideone.com/DxdNQI
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!