把人都送到房子里的最小花费--最小费用最大流MCMF

  1 #define IOS ios_base::sync_with_stdio(0); cin.tie(0);
  2 #include <cstdio>//sprintf islower isupper
  3 #include <cstdlib>//malloc  exit strcat itoa system("cls")
  4 #include <iostream>//pair
  5 #include <fstream>//freopen("C:\\Users\\13606\\Desktop\\Input.txt","r",stdin);
  6 #include <bitset>
  7 //#include <map>
  8 //#include<unordered_map>
  9 #include <vector>
 10 #include <stack>
 11 #include <set>
 12 #include <string.h>//strstr substr
 13 #include <string>
 14 #include <time.h>// srand(((unsigned)time(NULL))); Seed n=rand()%10 - 0~9;
 15 #include <cmath>
 16 #include <deque>
 17 #include <queue>//priority_queue<int, vector<int>, greater<int> > q;//less
 18 #include <vector>//emplace_back
 19 //#include <math.h>
 20 #include <cassert>
 21 //#include <windows.h>//reverse(a,a+len);// ~ ! ~ ! floor
 22 #include <algorithm>//sort + unique : sz=unique(b+1,b+n+1)-(b+1);+nth_element(first, nth, last, compare)
 23 using namespace std;//next_permutation(a+1,a+1+n);//prev_permutation
 24 //******************
 25 int abss(int a);
 26 int lowbit(int n);
 27 int Del_bit_1(int n);
 28 int maxx(int a,int b);
 29 int minn(int a,int b);
 30 double fabss(double a);
 31 void swapp(int &a,int &b);
 32 clock_t __STRAT,__END;
 33 double __TOTALTIME;
 34 void _MS(){__STRAT=clock();}
 35 void _ME(){__END=clock();__TOTALTIME=(double)(__END-__STRAT)/CLOCKS_PER_SEC;cout<<"Time: "<<__TOTALTIME<<" s"<<endl;}
 36 //***********************
 37 #define rint register int
 38 #define fo(a,b,c) for(rint a=b;a<=c;++a)
 39 #define fr(a,b,c) for(rint a=b;a>=c;--a)
 40 #define mem(a,b) memset(a,b,sizeof(a))
 41 #define pr printf
 42 #define sc scanf
 43 #define ls rt<<1
 44 #define rs rt<<1|1
 45 typedef pair<int,int> PII;
 46 typedef vector<int> VI;
 47 typedef long long ll;
 48 const double E=2.718281828;
 49 const double PI=acos(-1.0);
 50 //const ll INF=(1LL<<60);
 51 const int inf=(1<<30);
 52 const double ESP=1e-9;
 53 const int mod=(int)1e9+7;
 54 const int N=(int)1e5+10;
 55 
 56 int n,m,S,T;
 57 class MCMF
 58 {
 59 public:
 60     struct node
 61     {
 62         int u,v,f,w,nxt;
 63     }edge[N];
 64     int head[N],tot;
 65     int h[N],dis[N],PrePoint[N],PreEdge[N];
 66     void Init(int n)
 67     {
 68         tot=-1;
 69         for(int i=0;i<=n;++i)
 70             head[i]=-1,h[i]=0;
 71     }
 72     void add(int x,int y,int f,int w)
 73     {
 74         ++tot;
 75         edge[tot]={x,y,f,w,head[x]};
 76         head[x]=tot;
 77     }
 78     void Add(int x,int y,int f,int w)
 79     {
 80         add(x,y,f,w);
 81         add(y,x,0,-w);
 82     }
 83     PII Dij()
 84     {
 85         int max_flow=0,min_cost=0;
 86         while(1)
 87         {
 88             priority_queue<PII>q;
 89             for(int i=1;i<=n;++i)
 90                 dis[i]=inf;
 91             dis[S]=0;
 92             q.push({0,S});
 93             while(!q.empty())
 94             {
 95                 PII now=q.top();q.pop();
 96                 if(-now.first!=dis[now.second])continue;
 97                 if(now.second==T)break;
 98                 for(int i=head[now.second];i!=-1;i=edge[i].nxt)
 99                 {
100                     int nowcost=edge[i].w+h[now.second]-h[edge[i].v];
101                     if(edge[i].f>0&&dis[edge[i].v]>dis[now.second]+nowcost)
102                     {
103                         dis[edge[i].v]=dis[now.second]+nowcost;
104                         q.push({-dis[edge[i].v],edge[i].v});
105                         PrePoint[edge[i].v]=now.second;
106                         PreEdge[edge[i].v]=i;
107                     }
108                 }
109             }
110             if(dis[T]==inf)break;
111             for(int i=0;i<=n;++i)h[i]+=dis[i];
112             int nowflow=inf;
113             for(int i=T;i!=S;i=PrePoint[i])
114                 nowflow=min(nowflow,edge[PreEdge[i]].f);
115             for(int i=T;i!=S;i=PrePoint[i])
116             {
117                 edge[PreEdge[i]].f-=nowflow;
118                 edge[PreEdge[i]^1].f+=nowflow;
119             }
120             max_flow+=nowflow;
121             min_cost+=nowflow*h[T];
122         }
123         return {max_flow,min_cost};
124     }
125 }G;
126 
127 char mp[103][103];
128 int id[103][103];
129 
130 int main()
131 {
132     int h,l;
133     while(sc("%d%d",&h,&l),h&&l)
134     {
135         S=h*l+1,T=h*l+2;
136         int cnt=0;
137         fo(i,1,h)
138             fo(j,1,l)
139                 sc("%1s",&mp[i][j]),id[i][j]=++cnt;
140         n=h*l+2;
141         G.Init(n);
142         for(int i=1;i<=h;++i)
143         {
144             for(int j=1;j<=l;++j)
145             {
146                 if(i>1)G.Add(id[i][j],id[i-1][j],inf,1);
147                 if(j>1)G.Add(id[i][j],id[i][j-1],inf,1);
148                 if(i<h)G.Add(id[i][j],id[i+1][j],inf,1);
149                 if(j<l)G.Add(id[i][j],id[i][j+1],inf,1);
150                 if(mp[i][j]=='m')G.Add(S,id[i][j],1,0);
151                 if(mp[i][j]=='H')G.Add(id[i][j],T,1,0);
152             }
153         }
154         PII ans=G.Dij();
155         pr("%d\n",ans.second);
156     }
157     return 0;
158 }
159 
160 /**************************************************************************************/
161 
162 int maxx(int a,int b)
163 {
164     return a>b?a:b;
165 }
166 
167 void swapp(int &a,int &b)
168 {
169     a^=b^=a^=b;
170 }
171 
172 int lowbit(int n)
173 {
174     return n&(-n);
175 }
176 
177 int Del_bit_1(int n)
178 {
179     return n&(n-1);
180 }
181 
182 int abss(int a)
183 {
184     return a>0?a:-a;
185 }
186 
187 double fabss(double a)
188 {
189     return a>0?a:-a;
190 }
191 
192 int minn(int a,int b)
193 {
194     return a<b?a:b;
195 }