Segment tree with lazy propagation for sum of intervals operation.

segmentTree_lazy_sum.cpp

#include <iostream>
#include <string>
#include <limits>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <algorithm>
#include <utility>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>
#include <climits>
using namespace std;
    // #define PR(x) cout << #x " = " << x << "\n";

int64_t arr[100006];
int64_t t[262200];
int64_t lazy[262200];

void build(int64_t node, int64_t a, int64_t b)
{
	if(a>b) return;
	if (a==b)
	{
		t[node]=arr[a];
		return;
	}
	
	build(node*2, a, (a+b)/2);
	build(node*2+1,(a+b)/2+1,b);
	
	t[node]=t[node*2]+t[node*2+1];
}

int64_t query(int64_t node, int64_t a, int64_t b, int64_t i, int64_t j)
{
	if(a>b||a>j||b<i) return 0;
	if (lazy[node] !=0 )
	{
		t[node]+=lazy[node]*(b-a+1);
		if (a!=b)
		{
			lazy[node*2]+=lazy[node];
			lazy[node*2+1]+=lazy[node];
		}
		lazy[node]=0;
	}
	
	if (a>=i && b<=j) return t[node];
	
	int64_t q1=query(node*2, a, (a+b)/2, i, j);
	int64_t q2=query(node*2+1, (a+b)/2+1, b, i, j);
	
	return q1+q2;
}

void update(int64_t node, int64_t a, int64_t b, int64_t i, int64_t j, int64_t inc)
{
	if(a>b) return;
	if (lazy[node]!=0)
	{
		t[node]+=lazy[node]*(b-a+1);
		if (a!=b)
		{
			lazy[node*2]+=lazy[node];
			lazy[node*2+1]+=lazy[node];
		}
		lazy[node]=0;
	}
	if(a>b||a>j||b<i) return;
	
	if (a>=i && b<=j)
	{
		t[node]+=inc*(b-a+1);
		if (a!=b)
		{
			lazy[node*2]+=inc;
			lazy[node*2+1]+=inc;
		}
		return;
	}
	
	update(node*2, a, (a+b)/2, i, j, inc);
	update(node*2+1, (a+b)/2+1, b,i, j, inc);
	t[node] = t[node*2] + t[node*2+1];
}
int main(int argc, char const *argv[])
{
	ios_base::sync_with_stdio(0);
	int64_t t,n,qu,q,p,a; cin>>t;
	int64_t inc;
	while(t--)
	{
		cin>>n>>qu;
		build(1,0,n-1);
		for (int i = 0; i < 262200; ++i) lazy[i]=0;
		while(qu--)
		{
			cin>>a;
			if (a==0)
			{
				cin>>p>>q>>inc;
				update(1,0,n-1,p-1,q-1,inc);
			}
			else
			{
				cin>>p>>q;
				cout<<query(1,0,n-1,p-1,q-1)<<endl;
			}
		}
		
	}
	return 0;
} 

HI! thnx for your code.I am trying to implement slightly different version.
If we want to replace the value in range [p-1,q-1] with "inc" instead of adding "inc" to it. What will be the changes in code? Can you help?

adi11, can you explain what are you specifically trying to do? I get the feeling you can use this same exact code but modify your own modelling of the problem you're trying to solve
EDIT: I know it's been a year, can you explain what you were trying to do or if you solved it?