POJ 1236 Network of Schools (强连通+缩点)

ft........这个题开始想错了，无限WA，后来看了DIS才知道，自己完全错了，这个题做的很郁闷........努力啊

不会Tarjan，丢人了，贴个连接，抓紧学习。

http://www.byvoid.com/blog/scc-tarjan/

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <memory.h>
#include <cmath>
#include <bitset>
#include <queue>
#include <vector>
using namespace std;

const int BORDER = (1<<20)-1;
const int MAXSIZE = 37;
const int MAXN = 205;
const int INF = 1000000000;
#define CLR(x,y) memset(x,y,sizeof(x))
#define ADD(x) x=((x+1)&BORDER)
#define IN(x) scanf("%d",&x)
#define OUT(x) printf("%d\n",x)
#define MIN(m,v) (m)<(v)?(m):(v)
#define MAX(m,v) (m)>(v)?(m):(v)
#define ABS(x) ((x)>0?(x):-(x))

using namespace std;

typedef struct{
    int v;
    int next;
}Edge;

Edge edge_p[MAXN*MAXN],edge_r[MAXN*MAXN];

int n,m,k,ans,index_p,index_r,cnt,ret1,ret2;
int net_p[MAXN],net_r[MAXN],order[MAXN],set[MAXN];
int in_dg[MAXN],out_dg[MAXN];
bool visit[MAXN];

void add_edge(Edge* edge,int* net,const int& u,const int& v,int& index)
{
    edge[index].v = v;
    edge[index].next = net[u];
    net[u] = index++;
}
int init()
{
    index_r = index_p = 0;
    CLR(net_p,-1);
    CLR(net_r,-1);
    CLR(visit,0);
    CLR(order,0);
    CLR(set,0);
    CLR(in_dg,0);
    CLR(out_dg,0);
    return 0;
}
int input()
{
    int tmp;
    for(int i = 1; i <= n; ++i)
    {
        for(int j = 0; ; ++j)
        {
            IN(tmp);
            if(!tmp)
                break;
            add_edge(edge_p,net_p,i,tmp,index_p);
            add_edge(edge_r,net_r,tmp,i,index_r);
        }
    }
    return 0;
}
void dfs_p(const int& u)
{
    visit[u] = true;
    for(int i = net_p[u]; i != -1; i = edge_p[i].next)
        if(!visit[edge_p[i].v])
            dfs_p(edge_p[i].v);
    order[++cnt] = u;
}
void dfs_r(const int& u)
{
    visit[u] = true;
    set[u] = cnt;
    for(int i = net_r[u]; i != -1; i = edge_r[i].next)
        if(!visit[edge_r[i].v])
            dfs_r(edge_r[i].v);
}
int find_dg()
{
    int i,j,tmp;
    ret1 = ret2 = 0;
    for(i = 1; i <= n; ++i)
        for(j = net_p[i]; j != -1; j = edge_p[j].next)
        {
            if(set[i] != set[edge_p[j].v])
            {
                in_dg[set[edge_p[j].v]] = 1;
                out_dg[set[i]] = 1;
            }
        }
    for(i = 1; i <= cnt; ++i)
    {
        if(!in_dg[i])
            ++ret1;
        if(!out_dg[i])
            ++ret2;
    }
    return 0;
}
int work()
{
    int i,j,tmp,u,v;
    CLR(visit,0);
    cnt = 0;
    for(i = 1; i <= n; ++i)
        if(!visit[i])
            dfs_p(i);
    CLR(visit,0);
    cnt = 0;
    for(i = n; i > 0; --i)
        if(!visit[order[i]])
        {
            ++cnt;
            dfs_r(order[i]);
        }
    find_dg();
    if(cnt == 1)
        printf("1\n0\n");
    else
        printf("%d\n%d\n",ret1,MAX(ret1,ret2));
    return 0;
}
int main()
{
    while(IN(n)!=EOF)
    {
        init();
        input();
        work();
    }
    return 0;
}