【DFS】洛谷P6566 [NOI Online #3 入门组]观星（民间数据）

Link

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Problem

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Sample-1 in

5 7
*......
..**..*
.*...*.
...*...
....*..

Sample-1 out

3 4

Sample-2 in

10 10
**..**.**.
***....*..
*...**.**.
...*..*...
..........
**...**.*.
..*.*....*
..........
***..*.*..
.***..*...

Sample-2 out

4 12

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思路

这天空如此狭小
暴力。
dfs处理每个星座，桶排序处理星系。反正数据不大，随便敲。

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Code

#include
#include
#include
using namespace std;
int n,m,maxx,tongji,a[2001][2001],b[2001][2001],ans[100010];
int fx[10]={
     -1,0,1,-1,1,-1,0,1},fy[10]={
     -1,-1,-1,0,0,1,1,1};
char c;
bool check(int xx,int yy){
     
	if(xx == 0 || yy == 0 || xx > n || yy > m) return 0;
	return 1;
}
int dfs(int x,int y){
       //dfs得出此星座的大小
	int anss = 1;
	b[x][y] = 1;
	for(int i = 0; i < 8; ++i)
	  if(check(x+fx[i],y+fy[i]) == 1)  //单纯判断边界
	    if(b[x+fx[i]][y+fy[i]] == 0 && a[x+fx[i]][y+fy[i]] == 1)
	      anss += dfs(x+fx[i],y+fy[i]);
	return anss;
}
int main(){
     
	scanf("%d%d",&n,&m);
	for(int i = 1; i <= n; ++i)  //输入
	for(int j = 1; j <= m; ++j){
     
		c = getchar();
		while(c!='*' && c!='.') c = getchar();
		if(c == '*') a[i][j] = 1;
	}
	for(int i = 1; i <= n; ++i)
	  for(int j = 1; j <= m; ++j)
	    if(b[i][j] == 0 && a[i][j] == 1)
	    	++ans[dfs(i,j)];   //这个星座加入大小为dfs(i,j)的星系
	for(int i = 1; i <= 100000; ++i)  //统计星系
	  if(ans[i] > 0){
     
	  	maxx = max(maxx,i*ans[i]);  //星系大小 = 星座大小*星座数
	  	++tongji;
	  }
	printf("%d %d",tongji,maxx);
}

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