求次短路和路径条数

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;

const int maxn=100000+10;
const int nil=1000000000;

struct my{
       int next;
       int v;
       int w;
};

bool vis[maxn][3];
int cnt[maxn][3],dist[maxn][3],fa,adj[maxn];
int n,m;
my bian[maxn*2];

void myinsert(int u,int v,int w){
     bian[++fa].v=v;
     bian[fa].next=adj[u];
     bian[fa].w=w;
     adj[u]=fa;
}


void dijikstar(int s,int t){
     for (int i=1;i<=n;i++) dist[i][1]=dist[i][2]=nil;
     cnt[s][1]=1;
     dist[s][1]=0;
     int falg,u;
     for (int i=1;i<2*n;i++){
            int minn=nil;
        for (int j=1;j<=n;j++){
            if(!vis[j][1]&&dist[j][1]<minn){
                minn=dist[j][1];
                u=j;
                falg=1;
            }
            else if(!vis[j][2]&&dist[j][2]<minn){
                minn=dist[j][2];
                u=j;
                falg=2;
            }
        }
        if(minn==nil) break;
        vis[u][falg]=1;
        for (int j=adj[u];j;j=bian[j].next){
            int v=bian[j].v;
            int w=bian[j].w;
            if(dist[v][1]>minn+w){
                dist[v][2]=dist[v][1];
                cnt[v][2]=cnt[v][1];
                dist[v][1]=minn+w;
                cnt[v][1]=cnt[u][falg];
            }
            else if(dist[v][1]==minn+w) cnt[v][1]+=cnt[u][falg];
            else if(dist[v][2]>minn+w){
                dist[v][2]=minn+w;
                cnt[v][2]=cnt[u][falg];
            }
            else if(dist[v][2]==minn+w) cnt[v][2]+=cnt[u][falg];
        }
     }
     int ans=0;
     if(dist[t][2]==dist[t][1]+1) ans=cnt[t][2]+cnt[t][1];
     else ans=cnt[t][1];
     printf("%d
",ans);
}

int main(){
    int u,v,w;
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%d%d",&n,&m);
        int s,t;
        memset(bian,0,sizeof(bian));
        memset(adj,0,sizeof(adj));
        memset(cnt,0,sizeof(cnt));
        memset(vis,0,sizeof(vis));
        for (int i=1;i<=m;i++){
            scanf("%d%d%d",&u,&v,&w);
            myinsert(u,v,w);
        }
        scanf("%d%d",&s,&t);
        dijikstar(s,t);
    }
return 0;
}