（连通图 模板题）Network of Schools--POJ--1236

  1 #include<cstdio>
  2 #include<cstdlib>
  3 #include<cmath>
  4 #include<iostream>
  5 #include<algorithm>
  6 #include<cstring>
  7 #include<vector>
  8 using namespace std;
  9 #define N 105
 10 
 11 struct Edge{int v, next;}e[N*N];
 12 
 13 int n, Time, bnt, cnt, top;
 14 int low[N], dfn[N], Head[N], sta[N], InStack[N], belong[N];
 15 
 16 void Init()
 17 {
 18     Time = bnt = cnt = top = 0;
 19     memset(low, 0, sizeof(low));
 20     memset(dfn, 0, sizeof(dfn));
 21     memset(Head, -1, sizeof(Head));
 22 }
 23 void Add(int u, int v)
 24 {
 25     e[cnt].v = v;
 26     e[cnt].next = Head[u];
 27     Head[u] = cnt++;
 28 }
 29 
 30 void Tarjan(int u)
 31 {
 32     int j;
 33     low[u] = dfn[u] = ++Time;
 34     InStack[u] = 1;
 35     sta[++top]=u;
 36 
 37     for(j=Head[u]; j!=-1; j=e[j].next)
 38     {
 39         int v = e[j].v;
 40 
 41         if(!dfn[v])
 42         {
 43             Tarjan(v);
 44             low[u] = min(low[u], low[v]);
 45         }
 46         else if(InStack[v])
 47             low[u] = min(low[u], dfn[v]);
 48     }
 49 
 50     if(dfn[u] == low[u])
 51     {
 52         ++bnt;
 53         do
 54         {
 55             j = sta[top--];
 56             InStack[j] = false;
 57             belong[j] = bnt;
 58         }while(u!=j);
 59     }
 60 }
 61 
 62 int main()
 63 {
 64     while(scanf("%d", &n)!=EOF)
 65     {
 66         int u, v, i, j;
 67 
 68         Init();
 69 
 70         for(i=1; i<=n; i++)
 71         {
 72             while(scanf("%d", &v), v)
 73                 Add(i, v);
 74         }
 75 
 76         for(i=1; i<=n; i++)
 77             if(!dfn[i])
 78             Tarjan(i);
 79 
 80         int r[N]={0}, c[N]={0}, rn=0, cn=0;
 81 
 82         for(i=1; i<=n; i++)
 83         for(j=Head[i]; j!=-1; j=e[j].next)
 84         {
 85             u = belong[i], v = belong[e[j].v];
 86             if(u!=v)
 87             {
 88                 c[u]++;
 89                 r[v]++;
 90             }
 91         }
 92 
 93         for(i=1; i<=bnt; i++)
 94         {
 95             if(r[i]==0) rn++;
 96             if(c[i]==0) cn++;
 97         }
 98 
 99         if(bnt == 1)
100             printf("1\n0\n");
101         else
102             printf("%d\n%d\n", rn, max(rn, cn));
103 
104     }
105     return 0;
106 }