Range Updates and Sums.cpp

//BISMILLAHIR RAHMANIR RAHEEM
//ALLAH IS WATCHING ME
// Shoeb Akibul Islam
// Dept of ICE, NSTU
#include<bits/stdc++.h>
using namespace std;

using ll = long long;
using pii= pair<ll,ll>;

const int N=900005;
ll mod= 1e9+7;

ll a[N];
template <typename T>
struct st{
    #define lc (n<<1)
    #define rc ((n<<1)+1)

    vector<T> t, lazy;

    st(T n){
        t.resize(4*n, 0);
        lazy.resize(4*n, 0);
    }
    inline void push(int n, int b, int e){ //change here
        if (lazy[n] == 0)
            return;
        t[n] = t[n] + 1LL * (e - b + 1) * lazy[n];
        if (b != e){
            lazy[lc] += lazy[n];
            lazy[rc] += lazy[n];
        }
        lazy[n] = 0;
    }

    inline T combine(T a, T b){ // change here
        return a+b;
    }
    inline void pull(int n){ // change here
        t[n]=t[lc]+t[rc];
    }
    void build(int n, int b, int e){
        lazy[n]=0; // change here
        if(b==e){
            t[n]=a[b];
            return;
        }
        T mid= (b+e)>>1;
        build(lc, b, mid);
        build(rc, mid+1, e);
        pull(n);
    }
    void update (int n, int b, int e, int i, int j, T v){
        push(n, b, e);
        if(j<b || i>e) return;
        if(i<=b and j>=e){
            lazy[n]=v; // set lazy
            push(n, b, e);
            return ;
        }
        int mid=(b+e)>>1;
        update(lc, b, mid, i, j, v);
        update(rc, mid+1, e, i, j, v);
        pull(n);
    }

    T query(int n, int b, int e, int i, int j){
        push(n, b,e);
        if(i>e || j<b) return 0; // change gere
        if(i<=b and e<=j) return t[n];
        int mid=(b+e)>>1;
        return combine(query(lc, b,mid, i,j), query(rc, mid+1, e, i, j));
    }
};

void solve(int tc)
{
    int n, q; cin >> n >> q;
    st<ll> s(n);
    for(int i = 1; i<=n; i++){
        int x; cin >> x;
        s.update(1, 1, n, i, i, x);
    }
    while(q--){
        int t; cin >> t;
        if(t == 1){
            int l, r, x; cin >> l >> r >> x;
            s.update(1, 1, n, l, r, x);
        }
        else if(t == 2){
            int l, r, x; cin >> l >> r >> x;
            s.update(1, 1, n, l, r, x);
        }
        else{
            int l, r; cin >> l >> r;
            s.query(1, 1, n, l, r);
        }
    }
}



signed main()
{
    int test_case=1;
//    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//    cin >> test_case;
    for(int i = 1; i <= test_case ; i++)
        solve(i);
    return 0;
}