POJ 3468 A Simple Problem with Integers(区间更新)

转载请注明出处：忆梦http://blog.csdn.net/yimeng2013/article/details/17192863

题目链接：http://poj.org/problem?id=3468

线段树功能: update:成段增加  query：区间求和

跟着NotOnlySuccess大牛学线段树

#include<cstdio>
#define maxn 111111
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
#define LL long long
LL sum[maxn<<2];
LL col[maxn<<2];

void PushUp(int rt)
{
	sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}


void Pushdown(int rt, int len)
{
	if(col[rt])
	{
		col[rt<<1] += col[rt];
		col[rt<<1|1] += col[rt];
		sum[rt<<1] += (len - (len >>1)) * col[rt];
		sum[rt<<1|1] += (len>>1) * col[rt];
		col[rt] = 0;
	}
}


void build(int l, int r, int rt)
{
	col[rt] = 0;
	if(l == r)
	{
		scanf("%lld", &sum[rt]);
		return;
	}
	int m = (l + r) >> 1;
	build(lson);
	build(rson);
	PushUp(rt);
}

void update(int L, int R, int c, int l, int r, int rt)
{
	if(L <= l && r <= R)
	{
		col[rt] += c;
		sum[rt] += (LL)(r-l+1)*c;
		return;
	}
	
	Pushdown(rt, r-l+1);
	int m = (l + r) >> 1;
	if(L <= m)
		 update(L,R,c,lson);
	if(R > m)
		update(L, R, c, rson);
	PushUp(rt);
}

LL query(int L, int R, int l, int r, int rt)
{
	if(L <= l && r <= R)
	{
		return sum[rt];
	}

	Pushdown(rt, r-l+1);
	LL ret = 0;
	int m = (l + r) >> 1;
	if(L <= m)
		ret += query(L, R, lson);
	if(R > m)
		ret += query(L, R, rson);
	return ret;

}

int main ()
{
	int n, m;
	while(scanf("%d %d", &n, &m) != EOF)
	{
		build(1, n, 1);

		char op[2];
		while(m--)
		{
			scanf("%s", op);
			if(op[0] == 'C')
			{
				int a, b, c;
				scanf("%d %d %d", &a, &b, &c);
				update(a, b, c, 1, n, 1);
			}
			else 
			{
				int a, b;
				scanf("%d %d", &a, &b);
				printf("%lld\n", query(a, b, 1, n, 1));
			}
		}
	}
	return 0;
}