Agressive Cows Question

Why am I getting a run time error for this?

#include
#include
using namespace std;
bool cowplace(int ar[],int c,int n,int sep)
{
int last=ar[0];
int count=1;
for(int i=1;i<n;i++)
{
if(ar[i]-last>=sep)
{
last=ar[i];
count++;

	if(count==c)
    	return true;
	}
}
return false;

}

int main() {

// your code here
int t;
cin>>t;
while(t--)
{
   
	int n,c;
	cin>>n>>c;
	int ar[10000];
	for(int i=0;i<n;i++)
	       cin>>ar[i];
	int ans=0;
	sort(ar,ar+n);
	int s=0;
	int e=ar[n-1]-ar[0];
	
	while(s<=e)
	{
		int mid=s+(e-s)/2;
    	bool cowskeep=cowplace(ar,c,n,mid);
		if(cowskeep)
		{
			ans=mid;
			s=mid+1;
		}
		else
		{
			e=mid-1;
		}
	}

      cout<<ans;
}
	return 0;

}