n个男孩n个女孩,女孩选男孩,每个女孩都要选到不同的人
k对女孩有相同选择标准,
女孩每轮都选择没选过的男孩,
问总共能选几轮。
思路:
女孩1..n,男孩n+1..2*n编号
由女孩到男孩建容量为1的边
起点st=2*n+1,到1..n建边;
n+1..2*n到终点ed=2*n+2建边
二分搜索最大容量即为答案。详见代码:
/*********************************************************
file name: hdu3081.cpp
author : kereo
create time: 2015年02月17日 星期二 22时23分44秒
*********************************************************/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<cmath>
#include<string>
#include<algorithm>
using namespace std;
typedef long long ll;
const int sigma_size=26;
const int N=200+50;
const int MAXN=100000+50;
const int inf=0x3fffffff;
const double eps=1e-8;
const int mod=1000000000+7;
#define L(x) (x<<1)
#define R(x) (x<<1|1)
#define PII pair<int, int>
#define mk(x,y) make_pair((x),(y))
int n,m,k,edge_cnt,top;
int fa[N];
int head[N],que[N],s[N],cur[N],gap[N],dep[N];
struct Edge{
int v,cap,flow,next;
}edge[MAXN];
PII mp[MAXN];
void init(){
edge_cnt=top=0;
memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int cap){
edge[edge_cnt].v=v; edge[edge_cnt].cap=cap;
edge[edge_cnt].flow=0; edge[edge_cnt].next=head[u]; head[u]=edge_cnt++;
edge[edge_cnt].v=u; edge[edge_cnt].cap=0;
edge[edge_cnt].flow=0; edge[edge_cnt].next=head[v]; head[v]=edge_cnt++;
}
int findset(int x){
return fa[x] == x ? x : fa[x]=findset(fa[x]);
}
void Union(int x,int y){
int fx=findset(x);
int fy=findset(y);
if(fx == fy)
return ;
fa[fx]=fy;
}
void bfs(int st,int ed){
int front=0,rear=0;
memset(gap,0,sizeof(gap));
memset(dep,-1,sizeof(dep));
dep[ed]=0; gap[0]=1; que[rear++]=ed;
while(front!=rear){
int u=que[front++];
for(int i=head[u];i!=-1;i=edge[i].next){
int v=edge[i].v;
if(dep[v]!=-1)
continue;
dep[v]=dep[u]+1; gap[dep[v]]++; que[rear++]=v;
}
}
}
int isap(int st,int ed){
bfs(st,ed);
memcpy(cur,head,sizeof(head));
int ans=0,u=st;
while(dep[st]<2*n+2){
if(u == ed){
int Min=inf,inser;
for(int i=0;i<top;i++){
if(edge[s[i]].cap-edge[s[i]].flow<Min){
Min=edge[s[i]].cap-edge[s[i]].flow;
inser=i;
}
}
for(int i=0;i<top;i++)
edge[s[i]].flow+=Min,edge[s[i]^1].flow-=Min;
ans+=Min; top=inser;
u=edge[s[top]^1].v;
continue;
}
int flag=0,v;
for(int i=cur[u];i!=-1;i=edge[i].next){
v=edge[i].v;
if(edge[i].cap>edge[i].flow && dep[v]+1 == dep[u]){
flag=1; cur[u]=i;
break;
}
}
if(flag){
s[top++]=cur[u]; u=v;
continue;
}
int d=2*n+2;
for(int i=head[u];i!=-1;i=edge[i].next){
int v=edge[i].v;
if(edge[i].cap>edge[i].flow && dep[v]<d){
cur[u]=i,d=dep[v];
}
}
gap[dep[u]]--;
if(!gap[dep[u]])
return ans;
dep[u]=d+1; gap[dep[u]]++;
if(u!=st)
u=edge[s[--top]^1].v;
}
return ans;
}
void Graph(int cap){
init();
int Map[N][N];
memset(Map,0,sizeof(Map));
for(int i=1;i<=n;i++){
addedge(0,i,cap);
addedge(i+n,2*n+1,cap);
}
for(int i=1;i<=m;i++){
int u=mp[i].first;
int v=mp[i].second;
for(int j=1;j<=n;j++){
if(findset(u) == findset(j)){
if(Map[j][v])
continue;
Map[j][v]=1;
addedge(j,n+v,1);
}
}
}
}
int main(){
int T;
scanf("%d",&T);
while(T--){
init();
scanf("%d%d%d",&n,&m,&k);
for(int i=1;i<=n;i++)
fa[i]=i;
for(int i=1;i<=m;i++){
int u,v;
scanf("%d%d",&u,&v);
mp[i]=mk(u,v);
}
for(int i=0;i<k;i++){
int u,v;
scanf("%d%d",&u,&v);
Union(u,v);
}
int ans=0,l=0,r=n;
while(l<=r){
int mid=(l+r)>>1;
Graph(mid);
int res=isap(0,2*n+1);
if(res>=n*mid){
ans=mid;
l=mid+1;
}
else
r=mid-1;
}
printf("%d\n",ans);
}
return 0;
}