学步园

以后多看多做英文题，看不懂也要看！

最小的启动次数 ，意思就是用最少得点覆盖所有的边

最小顶点覆盖=最大二分匹配数

#include<stdio.h>
#include<string.h>
 
const int NV = 1505;
const int NE = 10000;
 
struct MaxMatch {
    int n, size;
    int head[NV];
    int aug[NV];
    bool mark[NV];
 
    struct Edge {
        int v, w, next;
        Edge () {}
        Edge (int V, int NEXT, int W = 0) : v(V), next(NEXT), w(W) {}
    }E[NE];
 
    inline void init(int vx) {
        n = vx, size = 0;
        for (int i = 0; i <= n; i++) {
            head[i] = -1;
        }
    }
 
    inline void insert(int u, int v, int w = 0) {
        E[size] = Edge(v, head[u], w);
        head[u] = size++;
    }
 
    inline int Hungary(int n) {
        int match = 0;
        memset(aug, -1, sizeof(aug));
        for (int i = 1; i <= n; i++) {
            if (aug[i] == -1) {//剪枝
                memset(mark, false, sizeof(mark));
                match += Find(i);
            }
        }
        return match;
    }
 
    inline bool Find(int u) {
        for (int i = head[u]; i != -1; i = E[i].next) {
            int v = E[i].v;
            if (mark[v]) continue;
            mark[v] = true;
            if (aug[v] == -1 || Find(aug[v])) {
                aug[v] = u, aug[u] = v;
                return true;
            }
        }
        return false;
    }
}g;
 
int main() {
       int k, m, n, a, b,c;
       while (scanf("%d", &n)&&n) 
	   {
           scanf("%d%d", &m, &k);
           g.init(m + n);
           while (k--) 
		   {
               scanf("%d%d%d", &c,&a,&b);
           //    if(a&&b) 不加限制条件也可以过
				   g.insert(a, b + n);
           }
         printf("%d\n", g.Hungary(n));
      }
   return 0;
}