Can someone find wrong test case for my solution?

Problem link : Contest Page | CodeChef
My Solution : Solution: 60500690 | CodeChef
PS : It’s passing all sample test cases but failing for some hidden cases , i am unable to find them please help.

consider below test case:

1
5
2 4 6 8 3

Your output is -1 but 3 2 4 6 8 can be the solution as the absolute differences will be 1 2 2 2 and the sum will be 7 which is odd.

Another problem with your solution is,
consider this test case

1
5
1 2 3 4 5

your output:

2 1 4 3 576556042672268600

res[4] gives the garbage value

1 Like

Thanks for your help , but still it is giving wa

#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
#include <unordered_map>
#include <cmath>

using namespace std;

typedef long long int ll;

void solve(){
  ll n;
  cin>>n;
  vector<ll> v;
  vector<ll> even;
  vector<ll> odd;
  for(ll i=0;i<n;i++){
  	ll d;
  	cin>>d;
  	v.push_back(d);
  	if(d & 1 !=0){
  		odd.push_back(d);
  	}
  	else{
  		even.push_back(d);
  	}
  }
  sort(even.begin(),even.end());
  sort(odd.begin(),odd.end());
  ll es=even.size();
  ll os=odd.size();
  if(os==0 || es==0){
  	cout<<-1<<endl;
  }
  else if(odd.size() & 1 !=0){
      for(ll i=0;i<v.size();i++){
          cout<<v[i]<<" ";
      }
      cout<<endl;
  }
  else{
  	vector<ll> res;
  	ll e=0,o=0;
  	for(ll i=0;i<n;i++){
  		if(i&1!=0){
  		
  			res.push_back(even[e]);
  			e++;
  		}
  		else{
  			res.push_back(odd[o]);
  			o++;
  		}
  	}
  	for(ll i=0;i<n;i++){
    	cout<<res[i]<<" ";
    }
    cout<<endl;
  }
  
}
int main() {
	ll t=1;
	cin>>t;
	while(t--){solve();}
	return 0;
}

Your first case

Is correct.

But, I don’t think rest of solution is correct. If (odd.size () & 1) != 0 (which means there are odd number of odd parity elements in the array) the array need not be lovely. Consider following array

3 3 2 3

Also, why should printing odd and even alternatively do the job (in that last case) ?

NOTE : (a & b != 0) is equivalent to a & (b != 0) because of the operator precedence and I have assumed that you didn’t mean what you coded there.

P.S Please do explain your thought process as it can help others.