LuoguP2763 试题库问题(最大流)

Posted 2021-01-31 blog-dr-j

建图同_____

代码：

  1 #include<queue>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<algorithm>
  5 const int oo=0x3f3f3f3f;
  6 struct pnt{
  7     int hd;
  8     int lyr;
  9     int now;
 10 }p[10000];
 11 struct ent{
 12     int twd;
 13     int lst;
 14     int vls;
 15 }e[100000];
 16 int k,n;
 17 int s,t;
 18 int cnt;
 19 int sum;
 20 std::queue<int>Q;
 21 void ade(int f,int t,int v)
 22 {
 23     cnt++;
 24     e[cnt].twd=t;
 25     e[cnt].vls=v;
 26     e[cnt].lst=p[f].hd;
 27     p[f].hd=cnt;
 28     return ;
 29 }
 30 bool Bfs(void)
 31 {
 32     while(!Q.empty())
 33         Q.pop();
 34     for(int i=1;i<=t;i++)
 35         p[i].lyr=0;
 36     p[s].lyr=1;
 37     Q.push(s);
 38     while(!Q.empty())
 39     {
 40         int x=Q.front();
 41         Q.pop();
 42         for(int i=p[x].hd;i;i=e[i].lst)
 43         {
 44             int to=e[i].twd;
 45             if(p[to].lyr==0&&e[i].vls>0)
 46             {
 47                 p[to].lyr=p[x].lyr+1;
 48                 if(to==t)
 49                     return true;
 50                 Q.push(to);
 51             }
 52         }
 53     }
 54     return false;
 55 }
 56 int Dfs(int x,int fll)
 57 {
 58     if(x==t)
 59         return fll;
 60     for(int& i=p[x].now;i;i=e[i].lst)
 61     {
 62         int to=e[i].twd;
 63         if(p[to].lyr==p[x].lyr+1&&e[i].vls>0)
 64         {
 65             int ans=Dfs(to,std::min(fll,e[i].vls));
 66             if(ans>0)
 67             {
 68                 e[i].vls-=ans;
 69                 e[((i-1)^1)+1].vls+=ans;
 70                 return ans;
 71             }
 72         }
 73     }
 74     return 0;
 75 }
 76 int Dinic(void)
 77 {
 78     int ans=0;
 79     while(Bfs())
 80     {
 81         int dlt;
 82         for(int i=1;i<=t;i++)
 83             p[i].now=p[i].hd;
 84         while(dlt=Dfs(s,oo))
 85             ans+=dlt;
 86     }
 87     return ans;
 88 }
 89 int main()
 90 {
 91     //freopen("a.in","r",stdin);
 92     scanf("%d%d",&k,&n);
 93     s=k+n+1;
 94     t=s+1;
 95     for(int i=1;i<=k;i++)
 96     {
 97         int v;
 98         scanf("%d",&v);
 99         sum+=v;
100         ade(i,t,v);
101         ade(t,i,0);
102     }
103     for(int i=1;i<=n;i++)
104     {
105         int p;
106         scanf("%d",&p);
107         ade(s,i+k,1);
108         ade(i+k,s,0);
109         for(int j=1;j<=p;j++)
110         {
111             int tp;
112             scanf("%d",&tp);
113             ade(i+k,tp,1);
114             ade(tp,i+k,0);
115         }
116     }
117     int tot=Dinic();
118     if(tot!=sum)
119     {
120         printf("No Solution!
");
121         return 0;
122     }
123     for(int i=1;i<=k;i++)
124     {
125         printf("%d:",i);
126         for(int j=p[i].hd;j;j=e[j].lst)
127         {
128             int to=e[j].twd;
129             if(to!=t&&e[j].vls>0)
130                 printf(" %d",to-k);
131         }
132         puts("");
133     }
134     return 0;
135 }