线段树 ： 区间更新 poj 3468 示例

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <vector>
#include <stack>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <map>
#include <set>
#include <iterator>
#include <algorithm>
#include <functional>
#include <utility>
#include <sstream>
#include <climits>
#include <cassert>
#define BUG puts("here!!!");
#define MID(x) (x) >> 1
#define L(x) (x) << 1
#define R(x) ((x) << 1 | 1)
using namespace std;
const int N = 100005;
struct Node {
	int a, b;
	long long sum;
	long long kind;
}t[4*N];
int n, m;
int r[N];
long long SUM;
void makeTree(int x, int y, int num) {
	t[num].a = x;
	t[num].b = y;
	t[num].kind = 0;
	if(x == y) t[num].sum = r[y];
	else {
	    int mid = MID(x+y);
		makeTree(x, mid, L(num));
		makeTree(mid+1, y, R(num));
		t[num].sum = t[L(num)].sum + t[R(num)].sum;
	}
}
void add(int x, int y, int z, int num) {
	if(x <= t[num].a && t[num].b <= y) { // 找终止节点
		t[num].sum += (t[num].b - t[num].a + 1) * z;
		t[num].kind += z;
	}
	else {
		if(t[num].kind != 0) {
			t[2*num].kind += t[num].kind;
			t[2*num+1].kind += t[num].kind;
			t[2*num].sum += (t[2*num].b - t[2*num].a + 1) * t[num].kind;
			t[2*num+1].sum += (t[2*num+1].b - t[2*num+1].a + 1) * t[num].kind;
			t[num].kind = 0;
		}
		int mid = MID(t[num].a + t[num].b);
		if(x <= mid) add(x, y, z, L(num));
		if(y > mid) add(x, y, z, R(num));
		t[num].sum = t[L(num)].sum + t[R(num)].sum;
	}
}
void query(int x, int y,  int num) {
	if(x <= t[num].a && t[num].b <= y) {
		SUM += t[num].sum;
	}
	else {
		if(t[num].kind != 0) {
			t[2*num].kind += t[num].kind;
			t[2*num+1].kind += t[num].kind;
			t[2*num].sum += (t[2*num].b - t[2*num].a + 1) * t[num].kind;
			t[2*num+1].sum += (t[2*num+1].b - t[2*num+1].a + 1) * t[num].kind;
			t[num].kind = 0;
		}
		int mid = MID(t[num].a + t[num].b);
		if(x <= mid) query(x, y, L(num));
		if(y > mid) query(x, y, R(num));
		t[num].sum = t[L(num)].sum + t[R(num)].sum;
	}
}
int main() {
	int i;
	scanf("%d%d", &n, &m);
	for(i = 1; i <= n; i++) {
		scanf("%d", &r[i]);
	}
	makeTree(1, n, 1);
	while(m--) {
		int a, b, c;
		char str[3];
		scanf("%s", str);
		if(str[0] == 'C') {
			scanf("%d%d%d", &a, &b, &c);
			add(a, b, c, 1);
		}
		else {
			scanf("%d%d", &a, &b);
			SUM = 0;
			query(a, b, 1);
			cout << SUM << endl;
		}
	}
	return 0;
}