这是我第一题AC的线段树

#include <cstdio>
#include <algorithm>
using std::min;
using std::max;
#define L(no) ((no) << 1)
#define R(no) (L(no) | 1)
#define PLUSTAG(no, val) plustag[no] += val, query[no] += val*(rb[no]-lb[no]+1)
const int MAXN = 400001;
int lb[MAXN], rb[MAXN], query[MAXN], ans, plustag[MAXN];
int sum(int a, int b) {return a + b;}
void build(int no, int l, int r) {
    int mid = l + r >> 1;
    lb[no] = l;
    rb[no] = r;
    if(l == r) scanf("%d", &query[no]);
    else {
        build(L(no), l, mid);
        build(R(no), mid + 1, r);
        query[no] = query[L(no)] + query[R(no)];
    }
}
void getval(int no, int l, int r, int(*func)(int, int), int* key) {
    int mid = lb[no] + rb[no] >> 1;
    if(l <= r && (lb[no] <= r&& rb[no] >= r || rb[no] >= l && lb[no] <= l)) {
        if(lb[no] == l && rb[no] == r) ans = func(ans, key[no]);
        else {
            if(plustag[no]) {
                PLUSTAG(L(no), plustag[no]);
                PLUSTAG(R(no), plustag[no]);
                plustag[no] = 0;
            }
            getval(L(no), l, min(mid, r), func, key);
            getval(R(no), max(l, mid + 1), r, func, key);
        }
    }
}
void plus(int no, int l, int r, int val) {
    int mid = lb[no] + rb[no] >> 1;
    if(l <= r && (lb[no] <= r&& rb[no] >= r || rb[no] >= l && lb[no] <= l)) {
        if(lb[no] == l && rb[no] == r) {
            PLUSTAG(no, val);
        }
        else {
            if(plustag[no]) {
                PLUSTAG(L(no), plustag[no]);
                PLUSTAG(R(no), plustag[no]);
                plustag[no] = 0;
            }
            query[no] += (r - l + 1) * val;
            plus(L(no), max(l, lb[no]), min(mid, r), val);
            plus(R(no), max(l, mid + 1), min(r, rb[no]), val);
        }
    }
}
int main() {
    int n, q, i, op, a, b, v;
    scanf("%d%d", &n, &q);
    build(1, 1, n);
    for(i = 1; i <= q; i++) {
        scanf("%d%d%d", &op, &a, &b);
        if(op == 0) {
            ans = 0;
            getval(1, a, b, sum, query);
            printf("%d\n", ans);
        }
        else {
            scanf("%d", &v);
            if(v != 0) plus(1, a, b, v);
        }
    }
    return 0;
}