Spoj problem STAMPS

STAMPS
#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;

int main(){
int sum=0,c=0;
int k,need,n;
scanf("%d",&k);
for(int t=0;t<k;t++){
scanf("%d",&need);
scanf("%d",&n);
int *arr=new int[n];
for(int i=0;i<n;i++){
scanf("%d",&arr[i]);
}
sort(arr,arr+n);
sum=0;
c=0;
for(int i=n-1;i>=0;i--){
sum+=arr[i];
//printf("%d %d\n",arr[i],sum);
c++;
if(sum>=need){
printf("Scenario #%d:\n%d\n",t+1,c);
break;
}
}
if(sum<need)
printf("Scenario #%d:\nimpossible\n",t+1);
}
}