HDU4292-Food-网络流

Posted 2020-06-14

裸网络流题。

  1 #include <cstdio>
  2 #include <algorithm>
  3 #include <cstring>
  4 #include <queue>
  5 using namespace std;
  6 
  7 const int maxn = 1200;
  8 const int maxe = 500000;
  9 const int inf = 1<<30;
 10 
 11 struct Edge
 12 {
 13     int v,cap,next;
 14 }edge[maxe];
 15 int level[maxn];
 16 int gap[maxn],pre[maxn],cur[maxn],head[maxn];
 17 
 18 int NV,NE;
 19 
 20 void add_edge(int u,int v,int cap)
 21 {
 22     edge[NE].v=v;
 23     edge[NE].cap=cap;
 24     edge[NE].next=head[u];
 25     head[u]=NE++;
 26 
 27     edge[NE].v=u;
 28     edge[NE].cap=0;
 29     edge[NE].next=head[v];
 30     head[v]=NE++;
 31 }
 32 
 33 void bfs(int vt)
 34 {
 35     memset(level,-1,sizeof(level));
 36     memset(gap,0,sizeof(gap));
 37     level[vt]=0;
 38     gap[level[vt]]++;
 39     queue<int>que;
 40     que.push(vt);
 41     while(!que.empty()) {
 42         int u=que.front();
 43         que.pop();
 44         for(int i=head[u]; i!=-1; i=edge[i].next) {
 45             int v=edge[i].v;
 46             if(level[v]!=-1)continue;
 47             level[v]=level[u]+1;
 48             gap[level[v]]++;
 49             que.push(v);
 50 
 51         }
 52     }
 53 }
 54 
 55 int SAP(int vs,int vt)
 56 {
 57     bfs(vt);
 58     memset(pre,-1,sizeof(pre));
 59     memcpy(cur,head,sizeof(head));
 60     int u=pre[vs]=vs,flow=0,aug=inf;
 61     gap[0]=NV;
 62     while(level[vs]<NV) {
 63         bool flag=false;
 64         for(int &i=cur[u]; i!=-1; i=edge[i].next) {
 65             int v=edge[i].v;
 66             if(edge[i].cap&&level[u]==level[v]+1) {
 67                 flag=true;
 68                 pre[v]=u;
 69                 u=v;
 70                 //  aug=(aug==-1?edge[i].cap:min(aug,edge[i].cap));
 71                 aug=min(aug,edge[i].cap);
 72                 if(v==vt) {
 73                     flow+=aug;
 74                     for(u=pre[v]; v!=vs; v=u,u=pre[u]) {
 75                         edge[cur[u]].cap-=aug;
 76                         edge[cur[u]^1].cap+=aug;
 77                     }
 78                     //     aug=-1;
 79                     aug=inf;
 80                 }
 81                 break;
 82             }
 83         }
 84         if(flag)continue;
 85         int minlevel=NV;
 86         for(int i=head[u]; i!=-1; i=edge[i].next) {
 87             int v=edge[i].v;
 88             if(edge[i].cap&&level[v]<minlevel) {
 89                 minlevel=level[v];
 90                 cur[u]=i;
 91             }
 92         }
 93         if(--gap[level[u]]==0)break;
 94         level[u]=minlevel+1;
 95         gap[level[u]]++;
 96         u=pre[u];
 97     }
 98     return flow;
 99 }
100 
101 int N,F,D;
102 
103 int main()
104 {
105     while(~scanf("%d%d%d",&N,&F,&D))
106     {
107         memset(head,-1,sizeof head);
108         NV = 2*N+F+D+1;NE=0;
109         int t;
110         char op[300];
111         for(int i=1;i<=F;i++)
112         {
113             scanf("%d",&t);
114             add_edge(0,i,t);
115         }
116         for(int i=1;i<=D;i++)
117         {
118             scanf("%d",&t);
119             add_edge(i+F,NV,t);
120         }
121         for(int i=1;i<=N;i++)
122         {
123             scanf("%s",op);
124             for(int j=1;j<=F;j++)
125                 if(op[j-1] == ‘Y‘)
126                     add_edge(j,i*2-1+D+F,1);
127         }
128         for(int i=1;i<=N;i++)
129             add_edge(i*2-1+D+F,i*2+D+F,1);
130 
131         for(int i=1;i<=N;i++)
132         {
133             scanf("%s",op);
134             for(int j=1;j<=D;j++)
135                 if(op[j-1] == ‘Y‘)
136                     add_edge(i*2+D+F,j+F,1);
137         }
138         printf("%d\n",SAP(0,NV));
139     }
140 }
141 /*
142 4 3 3
143 1 1 1
144 1 1 1
145 YYN
146 NYY
147 YNY
148 YNY
149 YNY
150 YYN
151 YYN
152 NNY
153 */