线段树模板(区间修改，区间查询)

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;

int n, m;
int w[N];
struct node {
    int l, r;
    LL sum, add;
}tr[N * 4];

void pushup(int u) {
    tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
}

void pushdown(int u) {
    auto &root = tr[u], &left = tr[u << 1], &right = tr[u << 1 | 1];
    if (root.add) {
        left.add += root.add, left.sum += (LL)(left.r - left.l + 1) * root.add;
        right.add += root.add, right.sum += (LL)(right.r - right.l + 1) * root.add;
        root.add = 0;
    }
}

void build(int u, int l, int r) {
    if (l == r) tr[u] = {l, r, w[l], 0};
    else {
        tr[u] = {l, r};//不要忘
        int mid = l + r >> 1;
        build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
        pushup(u);//pushup
    }
}

void modify(int u, int l, int r, int x) {
    if (tr[u].l >= l && tr[u].r <= r) {
        tr[u].sum += (LL)(tr[u].r - tr[u].l + 1) * x;
        tr[u].add += x;
    }
    else {
        pushdown(u);//modify之间要pushdown
        int mid = tr[u].l + tr[u].r >> 1;
        if (l <= mid) modify(u << 1, l, r, x);
        if (r > mid) modify(u << 1 | 1, l, r, x);
        pushup(u);//注意pushup
    }
}

LL query(int u, int l, int r) {
    if (tr[u].l >= l && tr[u].r <= r) return tr[u].sum;

    pushdown(u);
    int mid = tr[u].l + tr[u].r >> 1;
    LL ans = 0;
    if (l <= mid) ans = query(u << 1, l, r);
    if (r > mid) ans += query(u << 1 | 1, l, r);
    return ans;
}

int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i ++) cin >> w[i];

    build(1, 1, n);

    while (m --) {
        char op; cin >> op;
        int l, r, x;
        cin >> l >> r;

        if (op == 'Q') cout << query(1, l, r) << endl;
        else {
            cin >> x;
            modify(1, l, r, x);
        }
    }
    return 0;
}