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 }