searching why memory is not being allocated

Question

I Read all about the reasons for this error(SIGABRT) -> made this program using arrays and that gave me SIGSEGV. Please show me where have I asked for some memory which compiler cannot allocate or narrow it down to exact problem and where it resides??
Constraints are described below, and I've used long long int

1. 1 ≤ T ≤ 100
2. 1 ≤ N, K ≤ 100,000
3. 1 ≤ sum of K over all test cases ≤ 100,000
4. 1 ≤ Ai, Di ≤ 1,000,000 for each valid i
5. 1 ≤ Bi ≤ C for each valid i

6. Bi+1 < Bi for each valid i

   #include <bits/stdc++.h>
   using namespace std;
   typedef long long int ll;
   
   
   int main() {
   ll T;
   cin>>T;
   
   while(T--){
   
       ll N,K;
       cin>>N>>K;
   
       vector<ll> A(N,0);
       vector<ll> D(N,0);
       vector<ll> B(N,0);
   
       for(ll i=0; i<N ; i++){             // O(N)
           cin>>A[i];
       }
   
       for(ll i=0; i<N ; i++){             // O(N)
           cin>>D[i];
       }
   
       for(ll i=0; i<K ; i++){             // O(K)
           cin>>B[i];
       }
   
       ll vect_size=0;
   
       for(ll i=0; i<N ; i++)              // O(N)
           vect_size += D[i] ;
   
       //cout<<vect_size<<endl;
   
       vector<ll> cards(vect_size,0);
       ll sum=0;
   
   
       for(ll i=0; i<N ; i++){
   
           for(ll j=0; j<D[i] ; j++){
   
               cards[ sum+j ] = A[i] ;
           }
           sum+=D[i];
       }
   
   
      //sort(cards, cards+vect_size );                    // O(N.logN)  ::  N = vect_size
      sort(cards.begin(), cards.end());
   
       //----------------------game-begins-now-----------------------------------------
   
   
   
       ll left_lim=0;
       ll right_lim=vect_size-1;
       ll cur_size=vect_size;
   
       for(ll i=0; i<K; i++){
   
           if( i%2==0 ){
   
                   left_lim += cur_size-B[i] ;
                   cur_size  = B[i];
   
           }
           else{
   
                   right_lim -= cur_size-B[i];
                   cur_size  = B[i];
           }            
   
   
   
   
       }
   
       sum=0;
   
   
   
       for(ll i=left_lim; i<=right_lim; i++)
               sum += cards[i];
   
       cout<<sum<<"\n";
   
   
   }
   
   
   return 0;
   

   }

Answer 1

I am not clear what is the problem you are having (e.g., which line throws the error), but this can get you started:

1. Use std::vector<ll>::max_size() to get the maximum allowable size. This is possibly 2^30-1. Check if you are exceeding that.

2. If N < vect_size, line cards[ sum+j ] = A[i] is a problem.

3. vect_size can be up to LONG_MAX * LONG_MAX (see climits). LONG_MAX is possibly 2^31-1 or greater, so LONG_MAX * LONG_MAX may be approx. 2^62, which conceivably exceeds the limit in point 1. This is probably not what you want.

4. Depending on the specific contents of your vectors, the only other possibly problematic line is sum += cards[i].