\(\quad\) 裸的最大流。
#include <cstdio>
#include <cstring>
#include <queue>
const int MAXN = 4e3 + 19, MAXM = 4e6 + 19;
struct Edge{
int to, next, c;
}edge[MAXM];
int cnt = -1, head[MAXN];
inline void add(int from, int to, int c){
edge[++cnt].to = to;
edge[cnt].c = c;
edge[cnt].next = head[from];
head[from] = cnt;
}
int n, f, d;
int dep[MAXN];
int bfs(void){
std::queue<int>q; q.push(0);
std::memset(dep, 0, sizeof dep); dep[0] = 1;
while(!q.empty()){
int node = q.front(); q.pop();
for(int i = head[node]; i != -1; i = edge[i].next)
if(!dep[edge[i].to] && edge[i].c)
dep[edge[i].to] = dep[node] + 1, q.push(edge[i].to);
}
return dep[f + n + n + d + 1];
}
inline int min(const int& a, const int& b){
return a < b ? a : b;
}
int dfs(int node, int flow){
if(node == f + n + n + d + 1 || !flow)
return flow;
int stream = 0, f;
for(int i = head[node]; i != -1; i = edge[i].next)
if(dep[edge[i].to] == dep[node] + 1 && (f = dfs(edge[i].to, min(flow, edge[i].c)))){
flow -= f, stream += f;
edge[i].c -= f, edge[i ^ 1].c += f;
if(!flow)
break;
}
return stream;
}
int dinic(void){
int flow = 0;
while(bfs())
flow += dfs(0, 0x3f3f3f3f);
return flow;
}
int main(){
std::memset(head, -1, sizeof head);
std::scanf("%d%d%d", &n, &f, &d);
for(int i = 1; i <= f; ++i)
add(0, i, 1), add(i, 0, 0);
for(int i = f + 1; i <= f + n; ++i)
add(i, i + n, 1), add(i + n, i, 0);
for(int i = f + n + n + 1; i <= f + n + n + d; ++i)
add(i, f + n + n + d + 1, 1), add(f + n + n + d + 1, i, 0);
for(int a, b, i = 1; i <= n; ++i){
int l;
std::scanf("%d%d", &a, &b);
while(a--){
std::scanf("%d", &l);
add(l, f + i, 1), add(f + i, l, 0);
}
while(b--){
std::scanf("%d", &l);
add(f + n + i, f + n + n + l, 1), add(f + n + n + l, f + n + i, 0);
}
}
std::printf("%d\n", dinic());
return 0;
}