IOI2021集训队作业 210AI Sensor Network

平面图，两点右边当且仅当距离小于等于\(d\)。

求最大团。

\(n\le 100,d\le 10^4,|x_i|,|y_i|\le 10^4\)

---

随机排列若干次，然后贪心找最大团就对了？？？

---

using namespace std;
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 105
int n,k;
struct DOT{
	int x,y;
} d[N];
int p[N];
int e[N][N];
int q[N],nq;
int ansq[N],ans;
bool judge(int x){
	for (int i=1;i<=nq;++i)
		if (!e[x][q[i]])
			return 0;
	return 1;	
}
int main(){
//	freopen("in.txt","r",stdin);
	scanf("%d%d",&n,&k);
	for (int i=1;i<=n;++i)
		scanf("%d%d",&d[i].x,&d[i].y);
	for (int a=1;a<=n;++a)
		for (int b=1;b<=n;++b)
			e[a][b]=(((d[a].x-d[b].x)*(d[a].x-d[b].x)+(d[a].y-d[b].y)*(d[a].y-d[b].y)<=k*k));
	for (int i=1;i<=n;++i)
		p[i]=i;
	for (int T=1;T<=100000;++T){
		random_shuffle(p+1,p+n+1);
		nq=0;平面图，两点右边当且仅当距离小于等于$d$。

求最大团。

$n\le 100,d\le 10^4,|x_i|,|y_i|\le 10^4$

---

随机排列若干次，然后贪心找最大团就对了？？？

---

```cpp
using namespace std;
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 105
int n,k;
struct DOT{
	int x,y;
} d[N];
int p[N];
int e[N][N];
int q[N],nq;
int ansq[N],ans;
bool judge(int x){
	for (int i=1;i<=nq;++i)
		if (!e[x][q[i]])
			return 0;
	return 1;	
}
int main(){
//	freopen("in.txt","r",stdin);
	scanf("%d%d",&n,&k);
	for (int i=1;i<=n;++i)
		scanf("%d%d",&d[i].x,&d[i].y);
	for (int a=1;a<=n;++a)
		for (int b=1;b<=n;++b)
			e[a][b]=(((d[a].x-d[b].x)*(d[a].x-d[b].x)+(d[a].y-d[b].y)*(d[a].y-d[b].y)<=k*k));
	for (int i=1;i<=n;++i)
		p[i]=i;
	for (int T=1;T<=100000;++T){
		random_shuffle(p+1,p+n+1);
		nq=0;
		for (int i=1;i<=n;++i)
			if (judge(p[i]))
				q[++nq]=p[i];
		if (nq>ans){
			ans=nq;
			memcpy(ansq,q,sizeof(int)*(ans+1));
		}
	}
	printf("%d\n",ans);
	for (int i=1;i<=ans;++i)
		printf("%d ",ansq[i]);
	return 0;
}

	for (int i=1;i<=n;++i)
		if (judge(p[i]))
			q[++nq]=p[i];
	if (nq>ans){
		ans=nq;
		memcpy(ansq,q,sizeof(int)*(ans+1));
	}
}
printf("%d\n",ans);
for (int i=1;i<=ans;++i)
	printf("%d ",ansq[i]);
return 0;

}