关于线段树区间修改&查询

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
#define int long long
int sum[N << 2], lazy[N << 2], a[N];
int n, m;
void build(int l, int r, int rt){
    if(l == r){
        sum[rt] = a[l];
        return ;
    }
    int mid = (l + r) >> 1;
    build(l, mid, rt << 1);
    build(mid + 1, r, rt << 1 | 1);
}
void pushdown(int s, int t, int rt){
    int mid = (s + t) >> 1;
    if(lazy[rt]){
        lazy[rt << 1] += lazy[rt];
        lazy[rt << 1 | 1] += lazy[rt];
        sum[rt << 1] += lazy[rt] * (mid - s + 1);
        sum[rt << 1 | 1] += lazy[rt] * (t - mid);
        lazy[rt] = 0;
    }
//  sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];
}
void update(int s, int t, int l, int r, int w, int rt){
    if(l <= s && t <= r){
        sum[rt] += (t - s + 1) * w;
        lazy[rt] += w;
        return ;
    }
    int mid = (s + t) >> 1;
    if(l <= mid) update(s, mid, l, r,  w, rt << 1);
    if(r > mid) update(mid + 1, t, l, r, w, rt << 1 | 1);
    sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];
}
int ask(int s, int t, int l, int r, int rt){
    if(l <= s && t <= r) return sum[rt];
    pushdown(s, t, rt);
    int mid = (s + t) >> 1;
    int ans = 0;
    if(l <= mid) ans += ask(s, mid, l, r, rt << 1);
    if(mid < r) ans += ask(mid + 1, t, l, r, rt << 1 | 1);
    return ans;
}
void read() {
    scanf("%lld%lld", &n, &m);
    for (int i = 1; i <= n; ++i) scanf("%lld", &a[i]);
    build(1, n, 1);
    for (int i = 1; i <= m; ++i) {
        int id;
        scanf("%lld", &id);
        if(id == 1){
            int l, r, w;
            scanf("%lld%lld%lld", &l, &r, &w);
            update(1, n, l, r, w, 1);
        }else{
            int l, r;
            scanf("%lld%lld", &l, &r);
            printf("%lld\n", ask(1, n, l, r, 1));
        }
    }
}
signed main() {
    read();
    return 0;
}

rt, 求查错