1 #define _CRT_SECURE_NO_WARNINGS
2 /*
3 7 10
4 0 1 5
5 0 2 2
6 1 2 4
7 1 3 2
8 2 3 6
9 2 4 10
10 3 5 1
11 4 5 3
12 4 6 5
13 5 6 9
14 0 6
15 */
16 #include <iostream>
17 #include <vector>
18 #include <utility>
19 #include <queue>
20 #include <functional>
21 #include <algorithm>
22 #include <cstdio>
23 using namespace std;
24
25 const int maxn = 1010 + 20;
26 const int INF = 9999999;
27 int V, E;
28 int Prev[maxn]; //最短路上的前驱顶点
29 int d[maxn];
30 int cost[maxn][maxn]; //i->j 上的权值
31 int used[maxn];
32
33 void input();
34 void init();
35 //求从起点s出发到各个顶点的最短距离
36 void dijkstra(int s);
37
38 void init() {
39 for (int i = 0; i < V; i++) {
40 for (int j = 0; j < V; j++) {
41 if (i == j) {
42 cost[i][j] = 0;
43 }
44 else {
45 cost[i][j] = INF;
46 }
47 }
48 }
49 }
50
51 void input()
52 {
53 int s, t, ct;
54 for (int i = 0; i < E; i++) {
55 cin >> s >> t >> ct;
56 cost[s][t] = cost[t][s] = ct;
57 }
58 }
59
60 //从s点出发到各个顶点的最短距离
61 void dijkstra(int s)
62 {
63 fill(d, d + V, INF);
64 fill(used, used + V, false);
65 fill(Prev, Prev + V, -1);
66 d[s] = 0;
67
68 while (true) {
69 int v = -1;
70 for (int u = 0; u < V; u++) {
71 if (!used[u] && (v == -1 || d[u] < d[v]))
72 v = u; //找出到下一条尝试的顶点中距离最短的点
73 }
74
75 if (v == -1) break;
76 used[v] = true;
77
78 for (int u = 0; u < V; u++) {
79 if (d[u] > d[v] + cost[v][u]) {
80 d[u] = d[v] + cost[v][u]; //从v到各个临边u中最短的路-->存放到d[u]，用于下一次计算
81 Prev[u] = v; //u的前驱是v
82 }
83 }
84 }
85 }
86
87 //到顶点t的最短路
88 vector<int> get_path(int t) {
89 vector<int> path;
90 for (; t != -1; t = Prev[t]) path.push_back(t); //不断沿着Prev[t]走直到 t = s
91 //这样得到的是按照t到s的顺序，所以翻转之
92 reverse(path.begin(), path.end());
93 return path;
94 }
95
96
97 int main()
98 {
99 cin >> V >> E;
100 init();
101 input();
102 int st, ov;
103 cin >> st >> ov;
104 dijkstra(st);
105 cout << d[ov] << endl;
106 cout << "Debug..........
";
107 vector<int> path = get_path(ov);
108 for (int i = 0; i < path.size(); i++) {
109 cout << path[i] << " ";
110 }
111
112 cout << endl;
113 return 0;
114 }