luogu1078【2012普及】文化之旅(dfs)

加点剪枝，然后倒着爆搜，就A了。。。说好的最短路呢？？？

#include <bits/stdc++.h>using namespace std;#define N 110#define inf 0x3f3f3f3f#define ll long longinline 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,k,m,s,t,h[N],num=0,c[N],ans=inf;bool a[N][N];struct edge{    int to,next,val;}data[N*N<<1];struct TOT{    bool f[N];    TOT(){memset(f,0,sizeof(f));}}; inline void add1(int x,int y,int v){    data[++num].to=y;data[num].next=h[x];h[x]=num;data[num].val=v;}void dfs(int x,TOT f,int res){    if(x==s){ans=min(ans,res);return;}    if(res>=ans) return;    for(int i=1;i<=k;++i) if(a[i][c[x]]) f.f[i]=1;f.f[c[x]]=1;    if(f.f[c[s]]) return;    for(int i=h[x];i;i=data[i].next){        int y=data[i].to;        if(f.f[c[y]]) continue;dfs(y,f,res+data[i].val);    }}int main(){//  freopen("a.in","r",stdin);    n=read();k=read();m=read();s=read();t=read();    for(int i=1;i<=n;++i) c[i]=read();    for(int i=1;i<=k;++i)        for(int j=1;j<=k;++j)            a[i][j]=read();    while(m--){        int x=read(),y=read(),val=read();add1(x,y,val);add1(y,x,val);    }TOT f;    dfs(t,f,0);    if(ans==inf) puts("-1");    else printf("%d\n",ans);    return 0;}