模板-线段树

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

const int N = 1e5 + 10;
struct SegmentTree{
	int l, r;
	long long sum, add;
}t[N * 4]; 
int a[N], n, m;

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

void build(int p, int l, int r){
	t[p].l = l;
	t[p].r = r;
	if(l == r){
		t[p].sum = a[l];
		return;
	}
	int mid = l + r >> 1;
	build(p << 1, l, mid);
	build (p << 1 | 1, mid + 1, r);
	pushup(p);
}

void pushdown(int p) {
	if(t[p].add) {
		int ls = p << 1;
		int rs = p << 1 | 1;
		t[ls].sum += t[p].add * (t[ls].r - t[ls].l + 1);
		t[rs].sum += t[p].add * (t[rs].r - t[rs].l + 1);
		t[ls].add += t[p].add;
		t[rs].add += t[p].add;
		t[p].add = 0;
	}
}

void change(int p, int l, int r, int d) {
	if(l <= t[p].l && r >= t[p].r) {
		t[p].sum += (long long)d * (t[p].r - t[p].l + 1);
		t[p].add += d;
		return;
	}
	pushdown(p);
	int mid = t[p].l + t[p].r >> 1;
	if(l <= mid) change(p << 1, l, r, d);
	if(r > mid) change(p << 1 | 1, l, r, d);
	pushup(p);
}

long long ask(int p, int l, int r) {
	if(l <= t[p].l && r >= t[p].r) return t[p].sum;
	pushdown(p);
	int mid = t[p].l + t[p].r >> 1;
	long long val = 0;
	if(l <= mid) val += ask(p << 1, l, r);
	if(r > mid) val += ask(p << 1 | 1, l, r);
	return val;
}

int main() {
	int n, m;
	scanf("%d%d", &n, &m);
	for(int i = 1; i <= n ; i ++)
		scanf("%d", &a[i]);
	build(1, 1, n);
	int op, x, y, k;
	for(int i = 1; i <= m ; i ++) {
		scanf("%d%d%d", &op, &x, &y);
		if(op == 1){
			scanf("%d", &k);
			change(1, x, y, k);
		}
		else{
			printf("%lld\n", ask(1, x, y));
		}
	}
	return 0;
}

模板-线段树

原文：https://www.cnblogs.com/sjzez-llb/p/14002052.html