Implementation problem in segment tree problem

I am solving http://www.spoj.com/problems/HORRIBLE/ ,which is crashing on entering the first query.I am yet to implement the add function,but update function is not working .

long long int a[10000000];
long long int segtree[450000];
long long int lazy[450000];
void updatetree(int low,int high,int value,int qlow,int qhigh,int pos);
int main()
 {
   ios::sync_with_stdio(false);
   int t,b;
   long long int  n,c,p,q,v,i;
   cin>>t;
   while(t--)
   {
   //    memset(lazy,0,sizeof(lazy));
       cin>>n>>c;
       for(i=0;i<450000;i++)
       {
           lazy[i]=0;
           segtree[i]=0;
       }
       for(i=0;i<n;i++)
       a[i]=0;

       for(i=0;i<c;i++)
       {
        cin>>b;
        if(b==0)
        {
            cin>>p>>q>>v;
           updatetree(0,n-1,v,p,q,0);
        }
       /* else
        {
            cin>>p>>q;
            addtree(p,q);
        }*/
       }
     }
    return 0;
    }

   void updatetree(int low,int high,int value,int qlow,int qhigh,int pos)
    {
     if(lazy[pos]!=0)
      {
        segtree[pos]+=lazy[pos];
        if(low!=high)
          {

          lazy[2*pos+1]+=lazy[pos];
          lazy[2*pos+2]+=lazy[pos];
          }
          lazy[pos]=0;
     }
     if(qlow<=low&&qhigh>=high)
       {
        segtree[pos]+=value;
        if(low!=high)
        {
            lazy[2*pos+1]+=value;
            lazy[2*pos+2]+=value;
        }
      return ;
     }
     //if partial overlaps
     int mid;
     mid=(low+high)/2;
     updatetree(low,mid,value,qlow,qhigh,2*pos+1);
     updatetree(mid+1,high,value,qlow,qhigh,2+pos+2);
     segtree[pos]=min(segtree[2*pos+1],segtree[2*pos+2]);
    }