AC程式碼

#include<bits/stdc++.h>
using namespace std;

#define maxn 500
#define maxm 10000000
#define inf 0x3f3f3f3f
int first[maxn];
int edge_num;
int lev[maxn];
int vis[maxn];
int father[maxn];
int n,m,f;
vector<int>vec1[maxn];
set<int>vec2[maxn];
set<int>vec3[maxn];
struct edge{
    int u,v;
    int cap;
    int next;
}e[maxm];

int find(int x)
{
    return father[x]==x?x:father[x]=find(father[x]);
}

void merge(int a,int b)
{
    a=find(a);
    b=find(b);
    if(a!=b)
        father[a]=b;
}

void init()
{
    edge_num=0;
    memset(first,-1,sizeof(first));
}

void add_edge(int u,int v,int c)
{
    e[edge_num].u=u;
    e[edge_num].v=v;
    e[edge_num].cap=c;
    e[edge_num].next=first[u];
    first[u]=edge_num++;
    e[edge_num].u=v;
    e[edge_num].v=u;
    e[edge_num].cap=0;
    e[edge_num].next=first[v];
    first[v]=edge_num++;
}

int Dinic_spath(int s,int t)
{
    queue<int>q;
    q.push(s);
    memset(lev,-1,sizeof(lev));
    memset(vis,0,sizeof(vis));
    lev[s]=0;
    while(!q.empty())
    {
        int u=q.front();
        vis[u]=0;
        q.pop();
        for(int k=first[u];k!=-1;k=e[k].next)
        {
            int v=e[k].v;
            if(lev[v]==-1&&e[k].cap>0)
            {
                lev[v]=lev[u]+1;
                if(!vis[v])
                {
                    vis[v]=1;
                    q.push(v);
                }
            }
        }
    }
    return lev[t]!=-1;
}

int Dinic_dfs(int u,int t,int flow)
{
    int cost=0;
    if(u==t) return flow;
    for(int k=first[u];k!=-1;k=e[k].next)
    {
        int v=e[k].v;
        if(lev[v]==lev[u]+1&&e[k].cap>0)
        {
            int minn=Dinic_dfs(v,t,min(e[k].cap,flow-cost));
            if(minn>0)
            {
                e[k].cap=e[k].cap-minn;
                e[k^1].cap=e[k^1].cap+minn;
                cost+=minn;
                if(cost==flow) break;
            }
            else
                lev[v]=-1;
        }
    }
    return cost;
}

bool judge(int x)
{
    init();
    for(int i=1;i<=n;++i)
        add_edge(0,i,x);
    for(int i=1;i<=n;++i)
    {
        for(auto j=vec2[i].begin();j!=vec2[i].end();++j)
        {
            int v=*j;
            add_edge(i,n+v,1);
        }
    }
    for(int i=n+1;i<=2*n;++i)
        add_edge(i,2*n+1,x);
    int ans=0;
    while(Dinic_spath(0,2*n+1))
        ans+=Dinic_dfs(0,2*n+1,inf);
    return ans>=x*n;
}


int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d%d",&n,&m,&f);
        for(int i=0;i<=n;++i)
        {
            vec1[i].clear();
            vec2[i].clear();
            vec3[i].clear();
            father[i]=i;
        }
        for(int i=1;i<=m;++i)
        {
            int a,b;
            scanf("%d%d",&a,&b);
            vec1[a].push_back(b);
        }
        for(int i=1;i<=f;++i)
        {
            int a,b;
            scanf("%d%d",&a,&b);
            merge(a,b);
        }
        for(int i=1;i<=n;++i)
            vec3[find(i)].insert(vec1[i].begin(),vec1[i].end());
        for(int i=1;i<=n;++i)
            vec2[i]=vec3[find(i)];
        int l=0,r=n;
        int ans=0;
        while(l<=r)
        {
            int mid=(l+r)>>1;
            if(judge(mid))
            {
                ans=mid;
                l=mid+1;
            }
            else
                r=mid-1;
        }
        printf("%d\n",ans);
    }
}