教辅的组成

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<cmath>
#include<set>
#include<queue>
#define rep(i,a,n) for(int i = a;i <= n;i++)
#define per(i,n,a) for(int i = n;i >= a;i--)
#define enter putchar(‘\n‘)

using namespace std;
typedef long long ll;
const int M = 100005;
const int INF = 1000000009;

int read()
{
    int ans = 0,op = 1;
    char ch = getchar();
    while(ch < ‘0‘ || ch > ‘9‘)
    {
    if(ch == ‘-‘) op = -1;
    ch = getchar();
    }
    while(ch >= ‘0‘ && ch <= ‘9‘)
    {
    ans *= 10;
    ans += ch - ‘0‘;
    ch = getchar();
    }
    return ans * op;
}

struct edge
{
    int next,to,v,from;
}e[M<<1];

int n,m,k,p,qq,x,y,S,T,maxflow = 0,head[M],cur[M],dep[M],ecnt = -1;
queue <int> q;

void add(int x,int y,int z)
{
    e[++ecnt].to = y;
    e[ecnt].from = x;
    e[ecnt].next = head[x];
    e[ecnt].v = z;
    head[x] = ecnt;
}

bool bfs(int s,int t)
{
    memset(dep,-1,sizeof(dep));
    while(!q.empty()) q.pop();
    dep[s] = 0,q.push(s);
    rep(i,S,T) cur[i] = head[i];
    while(!q.empty())
    {
    int k = q.front();q.pop();
    for(int i = head[k];~i;i = e[i].next)
    {
        if(dep[e[i].to] == -1 && e[i].v)
        dep[e[i].to] = dep[k] + 1,q.push(e[i].to);
    }
    }
    return dep[t] != -1;
}

int dfs(int s,int t,int limit)
{
    if(s == t || !limit) return limit;
    int flow = 0;
    for(int i = cur[s];~i;i = e[i].next)
    {
    cur[s] = i;
    if(dep[e[i].to] != dep[s] + 1) continue;
    int f = dfs(e[i].to,t,min(limit,e[i].v));
    if(f)
    {
        e[i].v -= f,e[i^1].v += f;
        flow += f,limit -= f;
        if(!limit) break;
    }
    }
    if(!flow) dep[s] = -233333;
    return flow;
}

int main()
{
    memset(head,-1,sizeof(head));
    n = read(),m = read(),k = read(),S = 0,T = n * 2 + m + k + 1;
    p = read();
    rep(i,1,p) x = read(),y = read(),add(x+m+k,y,0),add(y,x+m+k,1);
    qq = read();
    rep(i,1,qq) x = read(),y = read(),add(x+m+n+k,y+m,1),add(y+m,x+m+n+k,0);
    rep(i,1,n) add(k+m+i,k+m+n+i,1),add(k+m+n+i,k+m+i,0);
    rep(i,1,m) add(S,i,1),add(i,S,0);
    rep(i,1,k) add(i+m,T,1),add(T,i+m,0);
    //rep(i,0,ecnt) printf("#%d %d %d\n",e[i].from,e[i].to,e[i].v);
    while(bfs(S,T)) maxflow += dfs(S,T,INF);
    printf("%d\n",maxflow);
    return 0;
}