1 #include <iostream>
2 #include <cstring>
3 #include <cstdio>
4 #include <algorithm>
5 #include <vector>
6 using namespace std;
7
8 typedef long long ll;
9 const int maxn = 100 + 5;
10 const int inf = 0x3f3f3f3f;
11 int n, m, ans;
12 int mp[maxn][maxn], dis[maxn][maxn], pos[maxn][maxn];
13 vector<int> path; //记录路径
14 inline void getpath( int x, int y ){
15 if( pos[x][y]==0 ) return;
16 getpath( x, pos[x][y] );
17 path.push_back(pos[x][y]);
18 getpath( pos[x][y], y );
19 }
20
21 inline void floyd(){
22 ans = inf;
23 for( int k=1; k<=n; k++ ){
24 for( int i=1; i<k; i++ )
25 for( int j=i+1; j<k; j++ )
26 if( (ll)dis[i][j] + mp[j][k] + mp[k][i] < ans ){
27 ans = dis[i][j]+mp[j][k]+mp[k][i];
28 path.clear(); //发现更优起点，清除之前路径
29 path.push_back(i); //该行到32行 按顺序插入才能构成环
30 getpath( i, j );
31 path.push_back(j);
32 path.push_back(k);
33 }
34 for( int i=1; i<=n; i++ )
35 for( int j=1; j<=n; j++ )
36 if( dis[i][j] > dis[i][k]+dis[k][j] ){ //此处要按dis[i][k]+dis[k][j]更新最短距离 而不是mp[i][k]+mp[k][j]
37 dis[i][j] = dis[i][k]+dis[k][j];
38 pos[i][j] = k;
39 }
40 }
41 }
42
43 int main(){
44 scanf("%d%d", &n, &m);
45 memset( mp, inf, sizeof(mp) );
46 memset( pos, 0, sizeof(pos) );
47 for( int i=0; i<=n; i++ ) mp[i][i] = 0;
48 for( int i=0; i<m; i++ ){
49 int u, v, w;
50 scanf("%d%d%d", &u, &v, &w);
51 if( w<mp[u][v] ) mp[u][v] = mp[v][u] = w;
52 }
53 memcpy( dis, mp, sizeof(mp) );
54 floyd();
55 if( ans==inf ){
56 puts("No solution.");
57 return 0;
58 }
59 for( int i=0; i<path.size(); i++ )
60 printf("%d ", path[i]);
61 puts("");
62
63 return 0;
64 }
65
66 /*
67 Sample Input
68 5 7
69 1 4 1
70 1 3 300
71 3 1 10
72 1 2 16
73 2 3 100
74 2 5 15
75 5 3 20
76
77 Sample Output
78 1 3 5 2
79 */
