USACO 5.3 Network of Schools(Tarjan)

我以前的Tarjan模版，全都敲错了。。。一个v写成了u，而且都AC了。。。

  1 /*
  2 ID: cuizhe
  3 LANG: C++
  4 TASK: schlnet
  5 */
  6 #include <iostream>
  7 #include <cstring>
  8 #include <cstdio>
  9 #include <cstdlib>
 10 using namespace std;
 11 #define N 10001
 12 #define M 500001
 13 struct node
 14 {
 15     int u,v,next;
 16 } edge[M+10];
 17 int t,top,scnt;
 18 int DFN[N+1],Low[N+1],Belong[N+1],stack[N+1],first[N+1],count[N+1];
 19 int in[N+1],input[N+1],output[N+1];
 20 int quex[M+1],quey[M+1];
 21 void CL()
 22 {
 23     t = 0;
 24     t = scnt = top = 0;
 25     memset(first,-1,sizeof(first));
 26     memset(DFN,0,sizeof(DFN));
 27     memset(input,0,sizeof(input));
 28     memset(output,0,sizeof(output));
 29     memset(count,0,sizeof(count));
 30 }
 31 void add(int u,int v)
 32 {
 33     edge[t].u = u;
 34     edge[t].v = v;
 35     edge[t].next = first[u];
 36     first[u] = t ++;
 37 }
 38 void Tarjan(int u)
 39 {
 40     int v,i;
 41     DFN[u] = Low[u] = ++ t;
 42     in[u] = 1;
 43     stack[top++] = u;
 44     for(i = first[u];i != -1;i = edge[i].next)
 45     {
 46         v = edge[i].v;
 47         if(!DFN[v])
 48         {
 49             Tarjan(v);
 50             if(Low[u] > Low[v])
 51             {
 52                 Low[u] = Low[v];
 53             }
 54         }
 55         else if(in[v] && Low[u] > DFN[v])
 56         {
 57             Low[u] = DFN[v];
 58         }
 59     }
 60     if(DFN[u] == Low[u])
 61     {
 62         scnt ++;
 63         do
 64         {
 65             v = stack[--top];
 66             in[v] = 0;
 67             Belong[v] = scnt;
 68         }while(u != v);
 69     }
 70 }
 71 int main()
 72 {
 73     int n,ev,i,tp;
 74     freopen("schlnet.in","r",stdin);
 75     freopen("schlnet.out","w",stdout);
 76     scanf("%d",&n);
 77     CL();
 78     tp = 0;
 79     for(i = 1; i <= n; i ++)
 80     {
 81         for(;;)
 82         {
 83             scanf("%d",&ev);
 84             if(ev == 0) break;
 85             quex[tp] = i;
 86             quey[tp] = ev;
 87             tp ++;
 88             add(i,ev);
 89         }
 90     }
 91     for(i = 1; i <= n; i ++)
 92     {
 93         if(!DFN[i])
 94         {
 95             Tarjan(i);
 96         }
 97     }
 98     for(i = 0; i < tp; i ++)
 99     {
100         if(Belong[quex[i]] != Belong[quey[i]])
101         {
102             int x = Belong[quex[i]];
103             int y = Belong[quey[i]];
104             output[x] = 1;
105             input[y] = 1;
106         }
107     }
108     int num1,num2;
109     num1 = num2 = 0;
110     if(scnt == 1)
111     {
112         printf("1\n0\n");
113         return 0;
114     }
115     for(i = 1; i <= scnt; i ++)
116     {
117         if(input[i] == 0)
118         {
119             num1 ++;
120         }
121         if(output[i] == 0)
122         {
123             num2 ++;
124         }
125     }
126     printf("%d\n",num1);
127     printf("%d\n",max(num1,num2));
128     return 0;
129 }

 

posted @ 2013-05-27 16:26  Naix_x  阅读(252)  评论(0)  编辑  收藏  举报