杭电1827--Summer Holiday（SCC + 缩点）

#include <stack>
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
const int INF = 0x3f3f3f3f;
int dfn[1001], low[1001], instack[1001], sccf[1001], Rdu[1001], Cost[1001], cnt_SCC, vis_num, total, n, m;
struct Edge
{
    int from, to, next;
} edge[2010];
int cnt, head[1001];
void Add(int a, int b)
{
    Edge E = {a, b, head[a]};
    edge[cnt] = E;
    head[a] = cnt++;
}
stack<int> S;
void TarJan(int x)
{
    int j;
    dfn[x] = low[x] = ++vis_num;
    instack[x] = 1;
    S.push(x);
    for(int  i = head[x]; i != -1; i = edge[i].next)
    {
        int u = edge[i].to;
        if(dfn[u] == -1)
        {
            TarJan(u);
            if(low[x] > low[u])
                low[x] = low[u];
        }
        else if(instack[u] && low[x] > dfn[u])
            low[x] = dfn[u]; 
    }
    if(low[x] == dfn[x])
    {
        cnt_SCC++;
        do{
            j = S.top();
            sccf[j] = cnt_SCC;
            S.pop(); 
            instack[j] = 0;
        }
        while(j != x);
    }
}
void Deal()   //确定结果； 
{
    for(int i = 1; i <= n; i++)
    {
        for(int k = head[i]; k != -1; k = edge[k].next)
        {
            int u = edge[k].to;
            if(sccf[u] != sccf[i])
                Rdu[sccf[u]]++;
        }
    }
    int ReSult = 0;
    for(int i = 1; i <= cnt_SCC; i++)
    {
        if(!Rdu[i])
        {
            ReSult++;
            int minn = INF; 
            for(int j = 1; j <= n; j++)
            { 
                if(sccf[j] == i)
                    minn = min(minn, Cost[j]);
            }
            total += minn;    
        }
    }
    printf("%d %d\n", ReSult, total);
}
void SolVe()
{
    vis_num = cnt_SCC = total = 0;
    for(int i = 1; i <= n; i++)
        if(dfn[i] == -1) 
            TarJan(i);
//    printf("%d\n", cnt_SCC);
} 
void GetMap()
{
    memset(Rdu, 0, sizeof(Rdu));
    memset(low, 0, sizeof(low)); 
    memset(dfn, -1, sizeof(dfn));
    memset(head, -1, sizeof(head));
    memset(instack, 0, sizeof(instack));
    
    cnt = 0;
    for(int i = 1; i <= m; i++)
    {
        int a, b;
        scanf("%d %d", &a, &b);
        Add(a, b);
    }
}
int main()
{
    while(~scanf("%d %d", &n, &m))
    {
        for(int i = 1; i <= n; i++)
            scanf("%d", &Cost[i]);
        
        GetMap();
        SolVe();
        Deal();
    }
    return 0;
}