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 http://icpc.upc.edu.cn/problem.php?id=2652

#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
struct str
{
    int t,n,v;
} e[100010];
int f[1010][1010],i,j,x,y,z,h[100010],t,n,m;
long long ans,d[1010];
void add(int x,int y,int v)
{
    t++;
    e[t].t=y;
    e[t].n=h[x];
    h[x]=t;
    e[t].v=v;
}
void spfa()
{
    queue<int>q;
    memset(d,0x3f,sizeof(d));
    d[1]=0;
    q.push(1);
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        for (int i=h[u]; i; i=e[i].n)
        {
            int v=e[i].t;
            if(d[v]>d[u]+e[i].v)
            {
                d[v]=d[u]+e[i].v;
                q.push(v);
            }
        }
    }
    for(int i=2; i<=n; ++i)
        ans+=d[i];
}
int main()
{
    memset(f,0x3f,sizeof(f));
    scanf("%d%d",&n,&m);
    for(i=1; i<=m; ++i)
    {
        scanf("%d%d%d",&x,&y,&z);
        f[x][y]=min(z,f[x][y]);
        add(x,y,z);
    }
    spfa();
    t=0;
    memset(h,0,sizeof(h));
    memset(e,0,sizeof(e));
    for(i=1; i<=n; ++i)
        for(j=1; j<=n; ++j)
            if(i!=j&&f[i][j]!=f[0][0])
                add(j,i,f[i][j]);
    spfa();
    printf("%lld\n",ans);
}