此题是最短路径生成树模板，求调qwq Wa On #8，开了long long，但在原来的题解上有修改

#include<bits/stdc++.h>
#define int long long 
#define printlf(x) print(x),putchar('\n')
#define printsp(x) print(x),putchar(' ')
using namespace std;
struct node{
    int now,dis;
    bool operator <(const node &x)  const{
        return x.dis<dis;
    }
};
const int N=3e5+5,M=3e5+5,INF=2147483647;
struct edge{
    int dis,to,next;
}Edge[M<<1];
bool vis[N];
int ans[N],head[N],dis[N],pre[N];
int cnt,sum,n,m,tot;
inline void add(int u,int v,int w){
    Edge[++tot].to=v;
    Edge[tot].next=head[u];
    Edge[tot].dis=w;
    head[u]=tot;
}
inline int read(){
    int x=0;
    bool w=0;
    char c=getchar();
    while(!isdigit(c))  w|=c=='-',c=getchar();
    while(isdigit(c))   x=(x<<1)+(x<<3)+(c^48),c=getchar();
    return w?-x:x;
}
inline void print(int x){
    if(x<0) x=-x,putchar('-');
    if(x>9) print(x/10);
    putchar('0'+x%10);
}
inline void Dijkstra(int s){
    priority_queue<node> q;
    for(register int i=1;i<=n;++i)    dis[i]=INF;
    q.push({s,0}),dis[s]=0;
    while(!q.empty()){
        int u=q.top().now;q.pop();
        if(vis[u])  continue;
        vis[u]=1;
        for(register int i=head[u];i;i=Edge[i].next){
            int v=Edge[i].to,w=Edge[i].dis;
            if(w+dis[u]<dis[v]){
                dis[v]=dis[u]+w;
                if(!vis[v])q.push({v,dis[v]}),pre[v]=i;
            }
            if(dis[v]==w+dis[u] && Edge[i].dis<Edge[pre[v]].dis)    pre[v]=i;
        }
    }
}
signed main(){
    n=read(),m=read();
    for(register int i=1;i<=m;++i){
        int u=read(),v=read(),w=read();
        add(u,v,w),add(v,u,w);
    }
    int s=read();
    Dijkstra(s);
    for(register int i=1;i<=n;++i){
        if(i==s)    continue;
        int id=pre[i],w=Edge[id].dis;
        sum+=w,ans[++cnt]=id;
    }
    // for(register int i=1;i<=n;++i)    cout<<pre[i]<<' ';cout<<endl;
    printlf(sum);
    sort(ans+1,ans+cnt+1);
    for(register int i=1;i<=cnt;++i)    printsp((ans[i]+1)>>1);
    return 0;
}