RT. 这题我去年 AC 的，现在发现之前的 AC 代码被 hack 了，WA 了一片。。。。。
dfs 做法，有 dalao 能看看哪有问题吗？

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
int n,m;
const int inf=0x3f3f3f3f;
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(!isdigit(ch))
    {
        if(ch=='-')f=-1;
        ch=getchar();
    }
    while(isdigit(ch))
    {
        x=(x<<1)+(x<<3)+(ch^48);
        ch=getchar();
    }
    return x*f;
}
const int maxn=13;
bool vis[maxn][maxn];
int imap[maxn][maxn];
int sd[maxn];//记录从起点到路径开始
int ans=inf;
int tot = 1;
int f[maxn] /*第几个点*/[maxn]/*深度*/[maxn]/*tot*/;
inline void memset()
{
    for(int i=0;i<13;i++)
        for(int j=0;j<13;j++)imap[i][j]=inf;
}
inline void memset2()
{
    for(int j=0;j<13;j++)sd[j]=0;
}
inline int min(int a,int b)
{
    return a<b?a:b;
}
void dfs(int x,int step,int cur)
{
    if(cur>ans)return;
 //   cout<<"step: "<<step<<endl;
    if(step==n)
    {
        ans=min(ans,cur);
   //     cout<<"cur: "<<cur<<endl;
        return;
    }
    for(register int to=1;to<=n;to++)
    {
        if(!sd[to])// mod zgc
        {
            for(register int u=1;u<=n;u++)
            {
                if(imap[u][to]!=inf&&sd[u]!=0)
                {
                    if(f[to][sd[u]+1][tot+1]<cur+sd[u]*imap[u][to])
                        continue;
                    if(cur+sd[u]*imap[u][to]>ans)continue;
                    f[to][sd[u] + 1][tot+1] = cur + sd[u] * imap[u][to];
                    sd[to]=sd[u]+1;
                    cur+=sd[u]*imap[u][to];
                    sd[to]=sd[u]+1;
                    tot++;
                    dfs(to,step+1,cur);
                    tot--;
                    cur-=sd[u]*imap[u][to];
                    sd[to]=0;
                }
            }
        }
    }
}
void dfs_henman(int x,int step,int cur)
{
    if(cur>ans)return;
 
    if(step==n)
    {
        ans=min(ans,cur);
        return;
    }
    for(register int to=1;to<=n;to++)
    {
        if(!sd[to])// mod zgc
        {
            for(register int u=1;u<=n;u++)
            {
                if(imap[u][to]!=inf&&sd[u]!=0)
                {
                    if(cur+sd[u]*imap[u][to]>ans)continue;
                    sd[to]=sd[u]+1;
                    cur+=sd[u]*imap[u][to];
                    sd[to]=sd[u]+1;
                    dfs_henman(to,step+1,cur);
                    cur-=sd[u]*imap[u][to];
                    sd[to]=0;
                }
            }
        }
    }
}
int main()
{
    memset();
    n=read();
    m=read();
    int x,y,v;
    for(register int i=1;i<=m;i++)
    {
        x=read();
        y=read();
        v=read();
        imap[x][y]=imap[y][x]=min(imap[x][y],v);
    }
    if(n>10)
    {
        for(register int i=1;i<=n;i++)
        {
            tot = 1;
            memset(f, 0x3f, sizeof(f));
            sd[i]=1;
            dfs(i,1,0);
            sd[i]=0;
        }
    }
    if(n<=10)
    {
        for(register int i=1;i<=n;i++)
        {
            sd[i]=1;
            dfs_henman(i,1,0);
            sd[i]=0;
        }
    }
    printf("%d",ans);
    return 0;
}