define n the number of ' * '
define d the number of couple of two points
define s the single point that can't link to others ( means no points around it in 4 directions )
n = 2 * d + s ;
d + s = n - d
use Hungary finding out the d
1 #include <stdio.h> 2 #include <string.h> 3 char gird[50][25]; 4 int number[50][25]; 5 int graph[1000][1000]; 6 int in[1000]; 7 int already[1000]; 8 int cnt; 9 10 struct node{ 11 int x,y; 12 }p[1000]; 13 int dir[4][2]={ 0,1,0,-1,-1,0,1,0}; 14 15 int find(int a){ 16 int i; 17 for(i=0;i<cnt;++i){ 18 if( graph[a][i]==1 && in[i]==0 ){ 19 in[i]=1; 20 if( already[i]==-1 || find( already[i] )){ 21 already[i]=a; 22 return 1; 23 } 24 } 25 } 26 return 0; 27 } 28 29 int main(){ 30 int t; 31 int n,m,i,j; 32 int tx,ty,tnum; 33 int res; 34 while(~scanf("%d",&t)){ 35 while(t--){ 36 res=0; 37 cnt=0; 38 memset(in,0,sizeof(in)); 39 memset(graph,0,sizeof(graph)); 40 for(i=0;i<1000;++i) already[i]=-1; 41 scanf("%d%d",&n,&m); 42 for(i=0;i<n;++i){ 43 scanf("%s",gird[i]); 44 for(j=0;j<m;++j) 45 if(gird[i][j]=='*'){ 46 number[i][j]=cnt; 47 p[cnt].x=i; 48 p[cnt].y=j; 49 cnt++; 50 } 51 } 52 for(i=0;i<cnt;++i){ 53 for(j=0;j<4;++j){ 54 tx=p[i].x+dir[j][0]; 55 ty=p[i].y+dir[j][1]; 56 if((!(tx>=0&&tx<n&&ty>=0&&ty<m))||gird[tx][ty]!='*') continue; 57 tnum=number[tx][ty]; 58 graph[i][tnum]=1; 59 } 60 } 61 for(i=0;i<cnt;++i){ 62 memset(in,0,sizeof(in)); 63 if(find(i)==1) 64 res++; 65 } 66 printf("%d ",cnt-res/2); 67 } 68 } 69 return 0; 70 } 71