segment_tree.cpp

#include<bits/stdc++.h>

using namespace std ;
#define M 500000
#define pii pair<int , int >
#define mp make_pair
#define mem(x , y) memset(x , y , sizeof x)
#define pf printf
#define sf scanf
#define sf1(a ) scanf("%d",&a)
#define pb push_back
#define sf2(a, b) scanf("%d%d",&a ,&b)
#define rep(i,n) for(i = 0 ; i< n ;i++ )

void tree[2*M] , arr[M] ;

void build(int node ,int r1 , int r2){

  if(r1 == r2)
  {
    tree[node] = arr[r1] ;
    return r1;
  }
  int left , right  , mid;
  left =  node*2 ;
  right =  node*2+1 ;
  mid = (r1 + r2)/2 ;
  build(left , r1 , mid);
  build(right ,mid+1 , r2);
  tree[node] = tree[left] + tree[right];


}

int query(int node , int r1 , int r2 , int i , int j ){
    if(r1 > j || i > r2) return 0 ;
    if( r1 >= i && r2 <= j ) return tree[node];
    int left , right , mid ;
    left =  node*2 ;
    right =  node*2 + 1;
    mid =  (r1+ r2 )/ 2;

    return query(left , r1 , mid,i ,j) + query(right  , mid+1 , r2 , i , j );


}


void query(int node , int r1 , int r2 , int i , int value ){
    if(r1 > i || i > r2) return 0 ;
    if( r1 >= i && r2 <= i ) return tree[node];
    int left , right , mid ;
    left =  node*2 ;
    right =  node*2 + 1;
    mid =  (r1+ r2 )/ 2;
    query(left , r1 , mid,i , value);
    query(right  , mid+1 , r2 , i , vlaue );

    tree[node] = tree[left ] + tree[right];

}

int main(){
// pf("hello world\n");







  return 0 ;
}