poj 3468 線段樹

#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <algorithm>
using namespace std;
const int MAXN = (int)1e5 + 10;
struct Node
{
	long long sum;
	int add;//延遲標記
	int left, right;
	int mid() { return (left + right) >> 1; }
} Tree[MAXN << 2];
int a[MAXN];

void buildTree(int i, int l, int r)
{
	Tree[i].add = 0;
	Tree[i].left = l;
	Tree[i].right = r;
	if (l == r)
	{
		Tree[i].sum = a[l];
		return;
	}
	int m = Tree[i].mid();
	buildTree(i << 1, l, m);
	buildTree(i << 1 | 1, m + 1, r);
	Tree[i].sum = Tree[i << 1].sum + Tree[i << 1 | 1].sum;
}

void push_up(int i)
{
	Tree[i].sum = Tree[i << 1].sum + Tree[i << 1 | 1].sum;
}

void push_down(int i)
{
	int lchild = i << 1;
	int rchild = i << 1 | 1;
	if (Tree[i].add)
	{
		Tree[lchild].add += Tree[i].add;
		Tree[rchild].add += Tree[i].add;
		Tree[lchild].sum += (long long)Tree[i].add * (Tree[lchild].right - Tree[lchild].left + 1);
		Tree[rchild].sum += (long long)Tree[i].add * (Tree[rchild].right - Tree[rchild].left + 1);
		Tree[i].add = 0;
	}
}

void updata(int i, int c, int l, int r)
{
	if (Tree[i].left == l && Tree[i].right == r)
	{
		Tree[i].add += c;
		Tree[i].sum += (long long)c * (r - l + 1);
		return;
	}
	if (Tree[i].left == Tree[i].right)
		return;
	push_down(i);
	int m = Tree[i].mid();
	if (r <= m)
		updata(i << 1, c, l, r);
	else if (l > m)
		updata(i << 1 | 1, c, l, r);
	else
	{
		updata(i << 1, c, l, m );
		updata(i << 1 | 1, c, m + 1, r);
	}
	push_up(i);
}


long long query(int i, int l, int r)
{
	if (Tree[i].left == l && Tree[i].right == r)
	{
		return Tree[i].sum;
	}
	push_down(i);
	int m = Tree[i].mid();
	if (r <= m)
	{
		return query(i << 1, l, r);
	}
	else if (l > m)
	{
		return query(i << 1 | 1, l, r);
	}
	else
	{
		return query(i << 1, l, m) + query(i << 1 | 1, m + 1, r);
	}
}

int main(void)
{
	ios::sync_with_stdio(false);
	
	int N, Q, x, y, c;
	char op;
	while (cin >> N >> Q)
	{
		for (int i = 1; i <= N; ++i)
			cin >> a[i];
		buildTree(1, 1, N);
		while (Q--)
		{
			cin >> op >> x >> y;
			if (op == 'Q')
				cout << query(1, x, y) << endl;
			else
			{
				cin >> c;
				updata(1, c, x, y);
			}
		}

	}

	return 0;
}