题目大意：
给你N个点 T条边， 求N->1的最短路
1 #include <iostream> 2 #include <cstdlib> 3 #include <cstdio> 4 #include <algorithm> 5 #include <vector> 6 #include <queue> 7 using namespace std; 8 #define INF 0xfffffff 9 #define maxn 1002 10 11 struct Edge 12 { 13 int e, w; 14 }; 15 16 vector<Edge> G[1002]; 17 bool vis[maxn]; 18 int dist[maxn], n, m;; 19 20 void Init() 21 { 22 for(int i=0; i<=n; i++) 23 { 24 G[i].clear(); 25 dist[i] = INF; 26 vis[i] = false; 27 } 28 } 29 int Spfa() 30 { 31 Edge P, Pn; 32 queue<Edge> Q; 33 P.e = n, P.w = 0; 34 dist[n] = 0; 35 Q.push(P); 36 37 while( !Q.empty() ) 38 { 39 P = Q.front(); 40 Q.pop(); 41 42 vis[P.e] = false; 43 int len = G[P.e].size(); 44 45 for(int i=0; i<len; i++) 46 { 47 Pn = G[P.e][i]; 48 49 if(dist[Pn.e] > dist[P.e] + Pn.w) 50 { 51 dist[Pn.e] = dist[P.e] + Pn.w; 52 53 if( !vis[Pn.e] ) 54 { 55 Q.push(Pn); 56 vis[Pn.e] = true; 57 } 58 } 59 } 60 } 61 return dist[1]; 62 } 63 int main() 64 { 65 Edge P; 66 67 while(cin >> m >> n) 68 { 69 Init(); 70 for(int i=0; i<m; i++) 71 { 72 int a, b ,c; 73 74 scanf("%d%d%d",&a,&b,&c); 75 76 P.e = b, P.w = c; 77 G[a].push_back(P); 78 P.e = a; 79 G[b].push_back(P); 80 } 81 82 int ans = Spfa(); 83 84 cout << ans << endl; 85 } 86 return 0; 87 }