Network of Schools(强连通分量+缩点） （问添加几个点最少点是所有点连接+添加最少边使图强连通)

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstdio>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<vector> 
 7 #include<stack>
 8 #define mem(x,y) memset(x,y,sizeof(x))
 9 using namespace std;
10 const int INF=0x3f3f3f3f;
11 const int MAXN=110;
12 vector<int>vec[MAXN];
13 stack<int>S;
14 int dfn[MAXN],low[MAXN],Instack[MAXN],in[MAXN],out[MAXN];
15 int dfs_blocks,scc,sccon[MAXN];
16 void targin(int u,int fa){
17     S.push(u);
18     Instack[u]=1;
19     dfn[u]=low[u]=++dfs_blocks;
20     for(int i=0;i<vec[u].size();i++){
21         int v=vec[u][i];
22         if(!dfn[v]){
23             targin(v,u);
24             low[u]=min(low[u],low[v]);
25         }
26         else if(Instack[v]){
27             low[u]=min(low[u],dfn[v]);
28         }
29     }
30     if(low[u]==dfn[u]){
31         scc++;
32         while(1){
33             int v=S.top();
34             S.pop();
35             Instack[v]=0;
36             sccon[v]=scc;
37             if(u==v)break;
38         }
39     }
40 }
41 int main(){
42     int N;
43     while(~scanf("%d",&N)){
44         scc=0;
45         for(int i=0;i<MAXN;i++)vec[i].clear();
46         while(!S.empty())S.pop();
47         mem(in,0);mem(out,0);mem(Instack,0);
48         mem(dfn,0);mem(low,0);mem(sccon,0);
49         for(int i=1;i<=N;i++){
50             int x;
51             while(scanf("%d",&x),x!=0){
52                 vec[i].push_back(x);
53             }
54         }
55         for(int i=1;i<=N;i++){
56             if(!dfn[i]){
57                 targin(i,-1);
58             }
59         }
60         for(int i=1;i<=N;i++){
61             for(int j=0;j<vec[i].size();j++){
62                 int v=vec[i][j];
63                 if(sccon[i]!=sccon[v])in[sccon[v]]++,out[sccon[i]]++;
64             }
65         }
66     //    printf("%d\n",scc);
67         int numin=0,numout=0;
68         if(scc==1){
69             puts("1\n0");continue;
70         }
71         for(int i=1;i<=scc;i++){
72             if(in[i]==0)numin++;
73             if(out[i]==0)numout++;
74         }
75         printf("%d\n%d\n",numin,max(numin,numout));
76     }
77     return 0;
78 }