poj-3468 区间操作

http://poj.org/problem?id=3468

区间求和操作 ，一个区间加操作。

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <iomanip>

using namespace std;

#define ll(ind) (ind<<1)
#define rr(ind) (ind<<1|1)
#define Mid(a,b) (a+((b-a)>>1))

typedef __int64 LL;

const int N = 100100;

int a[N];

struct node
{
	int left, right;
	LL sum, lazy;;
	int mid()
	{
		return Mid(left, right);
	}

	void fun(LL summ)
	{
		lazy += summ;
		sum += (right - left + 1) * summ;
	}
};

struct segtree
{
	node tree[N * 4];

	void real(int ind)//更新懒惰标记
	{
		if (tree[ind].lazy)
		{
			tree[ll(ind)].fun(tree[ind].lazy);
			tree[rr(ind)].fun(tree[ind].lazy);
			tree[ind].lazy = 0;
		}
	}

	void buildtree(int left, int right, int ind)//建树
	{
		tree[ind].left = left;
		tree[ind].right = right;
		tree[ind].sum = 0;
		tree[ind].lazy = 0;

		if (left == right)
		{
			tree[ind].sum = a[left];
		}

		if (left != right)
		{
			int mid = tree[ind].mid();
			buildtree(left, mid, ll(ind));
			buildtree(mid + 1, right, rr(ind));
			tree[ind].sum = tree[ll(ind)].sum + tree[rr(ind)].sum;
		}
	}

	void update(int st, int ed, int ind, int type)//更新
	{
		int left = tree[ind].left;
		int right = tree[ind].right;

		if (st <= left && right <= ed)
			tree[ind].fun(type);

		else
		{
			real(ind);

			int mid = tree[ind].mid();
			if (st <= mid) update(st, ed, ll(ind), type);
			if (ed > mid) update(st, ed, rr(ind), type);
			tree[ind].sum = tree[ll(ind)].sum + tree[rr(ind)].sum;
		}
	}

	LL query(int st, int ed, int ind)//求和
	{
		int left = tree[ind].left;
		int right = tree[ind].right;

		if (st <= left && right <= ed)
			return tree[ind].sum;
		else
		{
			real(ind);
			int mid = tree[ind].mid();

			LL s1 = 0, s2 = 0;
			if (st <= mid)
				s1 = query(st, ed, ll(ind));
			if (ed > mid)
				s2 = query(st, ed, rr(ind));

			return s1 + s2;
		}
	}
}seg;

int main()
{
	int n, m;
	int x, y, z;

	while (scanf("%d %d", &n, &m) != EOF)
	{
		for (int i = 1; i <= n; i++)
			scanf("%d", &a[i]);

		seg.buildtree(1, n, 1);

		char d[5];

		while (m--)
		{
			scanf("%s", d);
			if (d[0] == 'Q')
			{
				scanf("%d %d", &x, &y);
				cout << seg.query(x, y, 1) << endl;

			}
			else
			{
				scanf("%d %d %d", &x, &y, &z);
				seg.update(x, y, 1, z);
			}
		}
	}
	return 0;
}