lazy propagation

#include <iostream>
#include <math.h>
#include <algorithm>
#include <vector>
using namespace std;

void updaterange(int lazy[],int Arr[],int vs,int ve,int diff,int qs,int qe,int si)
{
    
    if(lazy[si]!=0)
    {
        Arr[si] +=(ve-vs+1)*lazy[si];
        
        if(vs!=ve)
        {
            lazy[si*2+1]+=lazy[si];
            lazy[si*2+2]+=lazy[si];
        }
        lazy[si]=0;
    }
    
    
    if(qs>ve || qe<vs )
        return;
    
    if(vs>=qs && qe<=ve)
    {
        Arr[si]+=(ve-vs+1)*diff;
        if(vs!=ve)
        {
            lazy[2*si+1] +=diff;
            lazy[2*si+2] +=diff;
            
        }
        return ;
    }
    
   
        int m  = (vs+ve)/2;
        updaterange(lazy,Arr,vs,m,diff,qs,qe,2*si+1);
        updaterange(lazy,Arr,m+1,ve,diff,qs,qe,2*si+2);
    
    Arr[si]= Arr[si*2+1] + Arr[si*2+2];
    
    
}


int getSum(int lazy[],int Arr[],int qs,int qe,int vs,int ve,int si )
{
    if(lazy[si]!=0)
    {
        Arr[si] +=(ve-vs+1)*lazy[si];
        
        if(vs!=ve)
        {
            lazy[si*2+1]+=lazy[si];
            lazy[si*2+2]+=lazy[si];
        }
        lazy[si]=0;
    }
    
    
    
    
    if(qs<=vs && qe>=ve)return Arr[si];
    
    if(ve<qs || vs>qe)return 0;
    
    int m = (vs+ve)/2;
    
    return getSum(lazy,Arr, qs,qe,vs,m,2*si+1)+ getSum(lazy,Arr, qs,qe,m+1,ve,2*si+2);
    
    
}


int construct(int lazy[],vector <int>& vec ,int Arr[],int vs,int ve,int si )
{
    
    if(vs==ve)
    {   //cout <<ss;
        Arr[si]=vec[ve];
        return Arr[si];
        
    }
    int m  =(vs+ve)/2;
    
    Arr[si]=construct(lazy,vec,Arr,vs,m,2*si+1)+construct(lazy,vec,Arr,m+1,ve,2*si+2);
    return Arr[si];
    
    
}


int main()
{
    vector < int  > vec;
    vec.push_back(1);
    vec.push_back(2);
    vec.push_back(3);
    vec.push_back(4);
    vec.push_back(5);
    vec.push_back(6);
    vec.push_back(7);
    vec.push_back(8);
    
    
    int v   = (int)vec.size();
    
    
    int n =  (int) ceil(log2(v));
    n=  (int)2* pow(2,n) - 1;
    
    int Arr[n];
    int lazy[n];
    for(int i=0;i<n;i++)lazy[i]=0;
    
    construct(lazy,vec,Arr,0,v-1,0);
    int qs = 0;
    int qe = 0;
    //diff = newval-oldval
    updaterange(lazy,Arr,0,v-1,1,0,3,0);
    int q = getSum(lazy,Arr,qs,qe,0,v-1,0);q = getSum(lazy,Arr,qs,qe,0,v-1,0);
    cout <<q;
    
    //for(int i=0;i<n;i++)
    // cout <<Arr[i]<<" ";
    
    
    return 1;
    
    
    
    
    
    
    
    
    
}