After reading some tutorials on segment tree:

• Efficient and easy segment trees

• Segment Tree by e-maxx

I thought to implement this data structure in Object Oriented methodology whereby I used vector instead of arrays in (contrast with tutorials) approach to hide implementation details, but it verdicts SIGSEGV for size in order of 10^5. But works fine (I hope) for array size less than of 10^4 order;

typedef struct SegmentTree{
   vector<int> tree, udp; int orgsize;
  /******************BUILD***********************/
  SegmentTree(vector<int>& list){ //CONSTRUCTOR
    orgsize=list.size();
    int size=((int)(pow(2,31-__builtin_clz(orgsize))))<<1;
    tree.resize(size); udp.assign(size,0); build(1,0,orgsize-1,list);
  }
  void build(int cur, int s, int e, vector<int>& list){
    if(s==e){ tree[cur]=list[s]; return ;}
    else{
      int mid=(s+e)/2;
      build(cur<<1,s,mid,list); build((cur<<1)+1,mid+1,e,list);
      tree[cur]= tree[cur<<1]+tree[(cur<<1)+1];     //NODE FUNCTION
    }
  }
  /***************  UPDATE  **************************/
  void update(int s, int e, int val){ update(1,0,orgsize-1,s,e,val);}
  void update(int cur, int ts, int te, int s, int e, int val){ //ts: temporary start, cur: current
    if(ts>=s && te<=e) udp[cur]+=val;
    else{
      tree[cur]+=(min(te,e)-max(ts,s)+1)*val;      //NODE FUNCTION
      int mid=(ts+te)/2;
      if(mid>=s && ts<=e) update(cur<<1,ts,mid,s,e,val);
      if(mid+1<=e && te>=s) update((cur<<1)+1,mid+1,te,s,e,val);
    }
  }
  /***************  QUERY ***************************/
  ll query(int s, int e){return q(1,0,orgsize-1,s,e);}
  ll q(int cur, int ts,int te, int s, int e){    //ts: temporary start, cur: current
    if(ts>=s && te<=e){
      if(udp[cur]!=0){
        tree[cur]+=(te-ts+1)*udp[cur];            //NODE FUNCTION
        if(2*cur < udp.size()){
          udp[cur<<1]+=udp[cur];
          udp[(cur<<1)+1]+=udp[cur];
        }
        udp[cur]=0;
      }
      return tree[cur];
    }
    else{
      tree[cur]+=(te-ts+1)*udp[cur];
      if((cur<<1) < udp.size()){
        udp[cur<<1]+=udp[cur];
        udp[(cur<<1)+1]+=udp[cur];
      }
      udp[cur]=0;
      ll temp=0; int mid=(ts+te)/2;
      if(mid>=s && ts<=e) temp+=q(cur<<1,ts,mid,s,e);
      if(mid+1<=e && te>=s) temp+=q((cur<<1)+1,mid+1,te,s,e);
      return temp;
    }
  }
} ST;

I tried this program for SPOJ-Horrible and get "Runtime error — SIGSEGV" which then I presume to arise from implementation as when I tried running on 10^5 it shows that error again.

My submission for above mention problem: Ideone

I tried using global vector of the object udp & tree and also the vector which I used to build this segment tree. But it didn't work. Is there a fix or shall I not use this OOP based implementation? Because

Thank you for having time to read this.!

UPD: Its solved! For those who are wondering the source of bug, it was in the calculation of size in constructor changing to 2 << (32 - __builtin_clz(orgsize - 1)) led to Accepted verdict.