HDOJ1150(最小点集覆盖)

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <vector>

using namespace std;

#define N 101

int match[N];
bool vis[N];
vector <int> e[N];
int n, m, k;

void InitRead();

void DataProcess();

bool Dfs(int x);

int main()
{
    while (~scanf("%d", &n))
    {
        if (n == 0) break;
        InitRead();
        DataProcess();
    }
    return 0;
}

void InitRead()
{
    scanf("%d %d", &m, &k);
    memset(match, -1, sizeof(match));
    for (int i=0; i<N; ++i) e[i].clear();
    int a, b;
    for (int i=0; i<k; ++i)
    {
        scanf("%*d %d %d", &a, &b);
        if (a == 0 || b == 0) continue;     //可以用模式0解决的任务不建边
        e[a].push_back(b);
    }
    return;
}

void DataProcess()
{
    int ans = 0;
    for (int i=0; i<n; ++i)
    {
        memset(vis, false, sizeof(vis));
        if (Dfs(i)) ans++;
    }
    printf("%d\n", ans);
    return;
}

bool Dfs(int x)
{
    int size = e[x].size();
    for (int i=0; i<size; ++i)
    {
        if (!vis[e[x][i]])
        {
            vis[e[x][i]] = true;
            if (match[e[x][i]] == -1 || Dfs(match[e[x][i]]))
            {
                match[e[x][i]] = x;
                return true;
            }
        }
    }
    return false;
}