代码

#include<bits/stdc++.h>

using namespace std;
const int N = 2e6+10;
int a[N],b[N],c[N],res[N],cnt[N],k[N],o[N];

struct hh
{
    int l,r; 
}h[N];

int main()
{
    int n,m,j = 0, t = 0; scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++) 
    {
        int x,y,z; scanf("%d %d %d",&x,&y,&z);
        h[x].l = y ,h[x].r = z;
    }
    int re = n;
    for(int i=1;i<=m;i++)
    {
        if(a[abs(h[re].l)] == 0){
               res[j] = re;
               cnt[j] = h[re].l; 
               j ++;
               a[abs(h[re].l)] ++;
        }else{
             k[t] = re;
             o[t] = h[re].l; 
             t ++;
        }
        re = h[re].r;
        if(re == -1) break;
    }

      for(int i=0;i<j;i++)
      {
        if(i != j-1)    printf("%05d %d %05d\n",res[i],cnt[i],res[i+1]);
        else    printf("%05d %d -1\n",res[i],cnt[i]);
      }
      for(int i=0;i<t;i++)
      {
        if(i != t-1)    printf("%05d %d %05d\n",k[i],o[i],k[i+1]);
        else    printf("%05d %d -1\n",k[i],o[i]);
      }


    return 0;
}