bzoj3380[Usaco2004 Open]Cave Cows 1 洞穴里的牛之一*

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define inc(i,j,k) for(int i=j;i<=k;i++)
 5 #define maxn 110
 6 using namespace std;
 7 
 8 inline int read(){
 9     char ch=getchar(); int f=1,x=0;
10     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
11     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();
12     return f*x;
13 }
14 struct e{int t,w,n;}es[maxn*20]; int g[maxn],ess;
15 void pe(int f,int t,int w){
16     es[++ess]=(e){t,w,g[f]}; g[f]=ess; es[++ess]=(e){f,w,g[t]}; g[t]=ess;
17 }
18 bool vis[maxn][17000]; int ans,a[17000],n,m,k,b[maxn];
19 void dfs(int x,int y){
20     if(vis[x][y])return; vis[x][y]=1; if(x==1)ans=max(ans,a[y]);
21     if(b[x]&&(y&(1<<(b[x]-1))))dfs(x,y^(1<<(b[x]-1)));
22     for(int i=g[x];i;i=es[i].n)if(es[i].w>=a[y])dfs(es[i].t,y);
23 }
24 int main(){
25     n=read(); m=read(); k=read(); inc(i,1,k){int x=read(); b[x]=i;}
26     inc(i,1,m){int x=read(),y=read(),z=read(); pe(x,y,z);}
27     inc(i,0,(1<<k)-1){inc(j,0,k-1)if(!(i&(1<<j)))a[i]++;} dfs(1,(1<<k)-1); printf("%d",ans); return 0;
28 }