poj2777--Count Color(线段树&&二进制)

版权声明：沃斯里德小浩浩啊 https://blog.csdn.net/Healer66/article/details/83047418

链接:

http://poj.org/searchproblem?field=source&key=POJ+Monthly--2006.03.26

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

const int maxn = 100005;
struct Segment
{
	int l,r;
	int status;//染色情况
	int cover;//lazy_tag
}tree[maxn<<2];
int n,color,m;

void build(int rt,int l,int r)
{
	tree[rt].l = l, tree[rt].r = r;
	tree[rt].status = tree[rt].cover = 1;
	if(l == r) return;
	int mid = (l + r) >> 1;
	build(rt<<1,l,mid);
	build(rt<<1|1,mid+1,r);
}

void update(int rt,int l,int r,int val)
{
	if(l <= tree[rt].l && tree[rt].r <= r)
	{
		tree[rt].status = 1 << (val - 1);
		tree[rt].cover = 1;
		return;
	}
	if(tree[rt].cover)
	{
		tree[rt<<1].cover = tree[rt<<1|1].cover = tree[rt].cover;
		tree[rt<<1].status = tree[rt<<1|1].status = tree[rt].status;
		tree[rt].cover = 0;
	}
	int mid = (tree[rt].l + tree[rt].r) >> 1;
	if(mid >= l) update(rt<<1,l,r,val);
	if (mid < r) update(rt<<1|1,l,r,val);//右区间是从mid+1开始的,所以不取等
	tree[rt].status = tree[rt<<1].status | tree[rt<<1|1].status;
	if(tree[rt<<1].cover && tree[rt<<1|1].cover && tree[rt<<1].status == tree[rt<<1|1].status)
		tree[rt].cover = 1;
}

int query(int rt,int l,int r)
{
	if(l <= tree[rt].l && tree[rt].r <= r)
		return tree[rt].status;
	if(tree[rt].cover) return tree[rt].status;
	int mid = (tree[rt].l + tree[rt].r) >> 1;
	int ans = 0;
	if(l <= mid) ans |= query(rt<<1,l,r);
	if(mid < r) ans |= query(rt<<1|1,l,r);
	return ans;
}

int main()
{
	char ch;
	int a,b,c;
	while(scanf("%d%d%d",&n,&color,&m)!=EOF)
	{
		build(1,1,n);
		while(m--)
		{
			getchar();
			scanf("%c",&ch);
			if(ch == 'C')
			{
				scanf("%d%d%d",&a,&b,&c);
				if(a > b) swap(a,b);
				update(1,a,b,c);
			}
			else
			{
				scanf("%d%d",&a,&b);
				if(a > b) swap(a,b);
				int ans = query(1,a,b),sum = 0;
				for(int i = 0; i < color; i++)
					if(ans & (1 << i))
						sum++;
				printf("%d\n",sum);
			}
		}
	}
	return 0;
}