Topic link: P2754 [CTSC1999] Homeland/Interstellar Transfer Problem
Analysis: I waive this question too many times, so I got PTSD, so I don’t want to say anything anymore.
#include<bits/stdc++.h>
#define pb push_back
using namespace std;
typedef long long ll;
const int maxn=1e5+7;
const int mod=1e9+7;
const int inf=0x3f3f3f3f;
int a[100][100],h[100],pre[maxn];
struct node {int to,cap,rev;};
int dep[maxn],n,m,S,T,k;
vector<node>v[maxn];
void add(int from,int to,int cap) //重边情况不影响
{
v[from].pb({to,cap,(int)v[to].size()});
v[to].pb({from,0,(int)v[from].size()-1});
}
int bfs(int s,int t)
{
queue<int>q;
memset(dep,-1,sizeof(dep));
dep[s]=0;
q.push(s);
while(!q.empty())
{
int u=q.front();
q.pop();
for(int i=0;i<v[u].size();i++)
if(v[u][i].cap>0&&dep[v[u][i].to]==-1)
{
dep[v[u][i].to]=dep[u]+1;
q.push(v[u][i].to);
}
}
return dep[t]!=-1;
}
int dfs(int u,int t,int micap)
{
if(u==t)return micap;
int tmp;
for(int i=0;i<v[u].size();i++)
{
node &now=v[u][i];
if(now.cap>0 && dep[u]+1==dep[now.to] && (tmp=dfs(now.to,t,min(now.cap,micap))))
{
now.cap-=tmp;
v[now.to][now.rev].cap+=tmp;
return tmp;
}
}
return 0;
}
int dinic(int s,int t)
{
int ans=0,tmp;
while(bfs(s,t))
while(1)
{
tmp=dfs(s,t,inf);
if(tmp==0)break;
ans+=tmp;
}
return ans;
}
int find(int x) {return (x==pre[x])?x:pre[x]=find(pre[x]);}
void merge(int x,int y)
{
int fx=find(x),fy=find(y);
if(fx!=fy) pre[fx]=fy;
}
void rua()
{
scanf("%d%d%d",&n,&m,&k);
for(int i=0;i<=n+1;i++) pre[i]=i;
for(int i=1;i<=m;i++)
{
scanf("%d%d",&h[i],&a[i][0]);
for(int j=1;j<=a[i][0];j++) {scanf("%d",&a[i][j]);if(a[i][j]==-1) a[i][j]=n+1;}
for(int j=1;j<a[i][0];j++)for(int l=j+1;l<=a[i][0];l++) merge(a[i][j],a[i][l]);
}
if(find(1)!=find(n+1)) {puts("0");return;}
S=20000;T=20001;
int earth=0,moon=n+1,sum=0;
for(int id=1;id<=1000;id++)
{
add(S,earth,inf);add(moon,T,inf);earth+=(n+2);moon+=(n+2);
for(int i=1;i<=m;i++)
{
int tmp=(id-1)%a[i][0]+1,res=tmp+1;
if(tmp==a[i][0]) res=1;
int x=a[i][tmp],y=a[i][res];
add(x+(id-1)*(n+2),y+id*(n+2),h[i]);
}
for(int i=1;i<=n;i++) add(i+(id-1)*(n+2),i+id*(n+2),inf);
int tot=dinic(S,T);sum+=tot;
//cout<<id<<' '<<tot<<endl;
if(sum>=k) {printf("%d\n",id-1);return;}
}
}
int main()
{
rua();
return 0;
}