http://poj.org/problem?id=2195
1 #include<cstdio> 2 #include<cstring> 3 #include<cmath> 4 #include<algorithm> 5 #include<queue> 6 #include<cstdlib> 7 #define maxn 500 8 using namespace std; 9 int n,mm; 10 char g[maxn][maxn]; 11 const int inf=1<<30; 12 13 struct node 14 { 15 int x,y; 16 }m[maxn]; 17 18 struct node1 19 { 20 int x,y; 21 }h[maxn]; 22 23 int cap[maxn][maxn]; 24 int cost[maxn][maxn]; 25 int flow[maxn][maxn]; 26 int p[maxn]; 27 int s,t; 28 int main() 29 { 30 while(scanf("%d%d",&n,&mm)&&n&&mm) 31 { 32 memset(cap,0,sizeof(cap)); 33 memset(cost,0,sizeof(cost)); 34 int t1=0,t2=0; 35 for(int i=0; i<n; i++) 36 { 37 scanf("%s",g[i]); 38 for(int j=0; j<mm; j++) 39 { 40 if(g[i][j]=='m') 41 { 42 m[++t1].x=i; 43 m[t1].y=j; 44 } 45 else if(g[i][j]=='H') 46 { 47 h[++t2].x=i; 48 h[t2].y=j; 49 } 50 } 51 } 52 for(int i=1; i<=t1; i++) 53 { 54 cap[0][i]=1; 55 cost[0][i]=0; 56 } 57 for(int i=1; i<=t1; i++) 58 { 59 for(int j=1; j<=t2; j++) 60 { 61 cap[i][t1+j]=1; 62 cost[i][t1+j]=abs(m[i].x-h[j].x)+abs(m[i].y-h[j].y); 63 cost[t1+j][i]=-cost[i][t1+j]; 64 } 65 } 66 for(int j=1; j<=t2; j++) 67 { 68 cap[t1+j][t1+t2+1]=1; 69 cost[t1+j][t1+t2+1]=0; 70 } 71 s=0,t=t1+t2+1; 72 queue<int>q; 73 int d[maxn]; 74 memset(flow,0,sizeof(flow)); 75 int c=0,f=0; 76 for(;;) 77 { 78 bool inq[maxn]; 79 for(int i=0; i<=t1+t2+1; i++) d[i]=(i==0?0:inf); 80 memset(inq,0,sizeof(inq)); 81 q.push(s); 82 while(!q.empty()) 83 { 84 int u=q.front();q.pop(); 85 inq[u]=false; 86 for(int v=0; v<=t1+t2+1; v++) if(cap[u][v]>flow[u][v] && d[v]>d[u]+cost[u][v]) 87 { 88 d[v]=d[u]+cost[u][v]; 89 p[v]=u; 90 if(!inq[v]) 91 { 92 inq[v]=true; 93 q.push(v); 94 } 95 } 96 } 97 if(d[t]==inf) break; 98 int a=inf; 99 for(int u=t; u!=s; u=p[u]) 100 { 101 if(cap[p[u]][u]-flow[p[u]][u]<a) 102 { 103 a=cap[p[u]][u]-flow[p[u]][u]; 104 } 105 } 106 for(int u=t; u!=s; u=p[u]) 107 { 108 flow[p[u]][u]+=a; 109 flow[u][p[u]]-=a; 110 } 111 c+=d[t]*a; 112 f+=a; 113 } 114 printf("%d ",c); 115 } 116 return 0; 117 }