loj6006「网络流 24 题」试题库（最大流）

判断是否满流即可。

#include <bits/stdc++.h>using namespace std;#define ll long long#define N 1510#define inf 0x3f3f3f3finline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-') f=-1;ch=getchar();}    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();    return x*f;}int n,a[N],h[N],num=1,T=1100,lev[N],tot=0;struct edge{    int to,next,val;}data[50000];inline void add(int x,int y,int val){    data[++num].to=y;data[num].next=h[x];h[x]=num;data[num].val=val;    data[++num].to=x;data[num].next=h[y];h[y]=num;data[num].val=0;}inline bool bfs(){    queue<int>q;memset(lev,0,sizeof(lev));    lev[0]=1;q.push(0);    while(!q.empty()){        int x=q.front();q.pop();        for(int i=h[x];i;i=data[i].next){            int y=data[i].to;if(lev[y]||!data[i].val) continue;            lev[y]=lev[x]+1;q.push(y);        }    }return lev[T];}inline int dinic(int x,int low){    if(x==T) return low;int tmp=low;    for(int i=h[x];i;i=data[i].next){        int y=data[i].to;if(lev[y]!=lev[x]+1||!data[i].val) continue;        int res=dinic(y,min(tmp,data[i].val));        if(!res) lev[y]=0;tmp-=res;data[i].val-=res;data[i^1].val+=res;        if(!tmp) return low;    }return low-tmp;}int main(){//  freopen("a.in","r",stdin);    int k=read();n=read();    for(int i=1;i<=k;++i){        int x=read();tot+=x;add(n+i,T,x);    }for(int i=1;i<=n;++i){        int owo=read();while(owo--) add(i,n+read(),1);add(0,i,1);    }int ans=0;while(bfs()) ans+=dinic(0,inf);    if(ans!=tot){puts("No Solution!");return 0;}    for(int x=1;x<=k;++x){        printf("%d:",x);        for(int i=h[x+n];i;i=data[i].next){            int y=data[i].to;if(y==T||!data[i].val) continue;            printf(" %d",y);        }puts("");    }return 0;}