1 #include <bits/stdc++.h>
 2 
 3 typedef long long LL;
 4 const int MAXN = 100;
 5 const int INF = 0x3f3f3f3f;
 6 using namespace std;
 7 
 8 int pre[MAXN + 3][MAXN + 3], dist[MAXN + 3][MAXN + 3]; //pre 儲存路徑; dist 儲存最短距離
 9 void floyd(int n, int gra[][MAXN + 3]) {
10     for(int i = 1; i <= n; i++) for
 
(int j = 1; j <= n; j++) dist[i][j] = gra[i][j], pre[i][j] = j;  //初始化
11     for(int k = 1; k <= n; k++) {   //嘗試經過 k 個點對每對頂點之間的距離進行更新
12         for(int i = 1; i <= n; i++) {
13             for(int j = 1; j <= n; j++) {
14                 if(dist[i][k] != INF && dist[k][j] != INF && dist[i][k] + dist[k][j] < dist[i][j]) {
 
15                     dist[i][j] = dist[i][k] + dist[k][j];
16                     pre[i][j] = pre[i][k];
17                 }
18             }
19         }
20     }
21 }
22 
23 int pfpath(int u, int v) { //列印最短路徑
24     while(u != v) {
25         cout << u  << " ";
26         u = pre[u][v];
 
27     }
28     cout << u << endl;
29 }
30 
31 int gra[MAXN + 3][MAXN + 3];
32 int main() {
33     int n, m;
34     while(cin >> n >> m){ // n 個點,  m 條邊
35         for(int i = 0; i <= n; i++) for(int j = -1; j <= n; j++){
36             gra[i][j] = (i == j ? 0 : INF);
37         }
38         for(int i = 0; i < m; i++) {
39             int u, v, w; cin >> u >> v >> w;
40             gra[u][v] = gra[v][u] = w;  //無向圖
41         }
42         floyd(n, gra);
43     }
44     return 0;
45 }