POJ 3020 Hungary

一道建图题……

// by SiriusRen#include <cstdio>#include <cstring>using namespace std;#define N 1666int h,w,v[N],next[N],first[N],tot,cnt,cases,map[55][55],fa[N],ans;char a[55][55],xx[]={1,-1,0,0},yy[]={0,0,1,-1},vis[N];void add(int x,int y){v[tot]=y,next[tot]=first[x],first[x]=tot++;}bool dfs(int x){    for(int i=first[x];~i;i=next[i])        if(!vis[v[i]]){            vis[v[i]]=1;            if(!fa[v[i]]||dfs(fa[v[i]]))                {fa[v[i]]=x;return 1;}        }    return 0;}int main(){    scanf("%d",&cases);    while(cases--){        tot=0;cnt=ans=0;memset(map,0,sizeof(map));        memset(first,-1,sizeof(first)),memset(fa,0,sizeof(fa));        scanf("%d%d",&h,&w);        for(int i=1;i<=h;i++)            for(int j=0;j<=w;j++){                scanf("%c",&a[i][j]);                if(a[i][j]=='*')map[i][j]=++cnt;                else map[i][j]=0;            }        for(int i=1;i<=h;i++)            for(int j=1;j<=w;j++)                if(map[i][j])                    for(int k=0;k<4;k++)                        if(map[i+xx[k]][j+yy[k]])                            add(map[i][j],map[i+xx[k]][j+yy[k]]);        for(int i=1;i<=cnt;i++,memset(vis,0,sizeof(vis)))            if(dfs(i))ans++;        printf("%d\n",cnt-ans/2);    }}