BIT-- POINT UPDATE AND RANGE QUERY !!!!

BIT-- POINT UPDATE AND RANGE QUERY !!!!

#include<iostream>
using namespace std;
#include<bits/stdc++.h>
 int arr[10000000];
  int tree[1000000];
   int n;

  // build tree
void build(int val,int index)
 {

  while(index<=n)
  {
 
  tree[index]+=val;
  index+=index & (-index);
 
 }
 }


 // increase ith index value by val ..
 void update(int val,int index)
  {
 
 
  int diff=val-arr[index];
  arr[index]=val;
    while(index<=n)
  {
 
  tree[index]+=diff;
  index+=index & (-index);
 
 }
  }
 
  // sum from index 1 to index
   int query(int index)
    {
   
    int sum=0;
    while(index!=0)
     {
      sum+=tree[index];
      index-=index & (-index);
 }
 return sum;
}


 int main()
  {
 
   cin>>n;
    for(int i=1;i<=n;i++)
     {
      cin>>arr[i];
 }

 for(int i=1;i<=n;i++)
  {
  build(arr[i],i);
  }

  int q;
   cin>>q;
   while(q--)
    {
    int type ;
     cin>>type;
     if(type==1)
      {
      cout<<" enter value  and index at which need to update !!!!"<<endl;
       int val ,index;// index   at which need to update if array is 1 based
       cin>>val>>index;
       update(val,index);
       cout<<" tree status "<<endl;
       for(int i=1;i<=n;i++) cout<<tree[i]<<" ";
       cout<<endl;
}
else
{
int index;
 cin>>index;// sum of fist index no of numbers ...
int ans=query(index);
cout<<ans<<endl;
}
}
 
  }