求1到N的最短路
注意有重边 跑一遍dijkstra就行
1 /* *********************************************** 2 Author :Sun Yuefeng 3 Created Time :2016/10/22 14:18:06 4 File Name :A.cpp 5 ************************************************ */ 6 7 #include<cstdio> 8 #include<iostream> 9 #include<algorithm> 10 #include<cmath> 11 #include<cstring> 12 #include<string> 13 #include<bitset> 14 #include<map> 15 #include<set> 16 #include<stack> 17 #include<vector> 18 #include<queue> 19 #include<list> 20 #define M(a,b) memset(a,b,sizeof(a)) 21 using namespace std; 22 typedef long long ll; 23 const int inf=0x3f3f3f3f; 24 const int maxn=1e3+10; 25 const int mod=1e7+7; 26 int dx[8]= {0,0,1,-1,1,-1,1,-1}; 27 int dy[8]= {1,-1,0,0,-1,1,1,-1}; 28 29 int n,m; 30 int way[maxn][maxn]; 31 int dis[maxn]; 32 bool vis[maxn]; 33 34 void dijkstra(int x){ 35 for(int i=1;i<=m;i++){ 36 dis[i]=inf; 37 vis[i]=false; 38 } 39 dis[x]=0; 40 for(int i=1;i<=m;i++){ 41 int k=-1; 42 int min=inf; 43 for(int j=1;j<=m;j++){ 44 if(!vis[j]&&dis[j]<min){ 45 min=dis[j]; 46 k=j; 47 } 48 } 49 if(k==-1) break; 50 vis[k]=true; 51 for(int j=1;j<=m;j++){ 52 if(!vis[j]&&dis[j]>dis[k]+way[j][k]){ 53 dis[j]=dis[k]+way[j][k]; 54 } 55 } 56 } 57 } 58 59 int main() 60 { 61 //freopen("in.txt","r",stdin); 62 //freopen("out.txt","w",stdout); 63 while(~scanf("%d%d",&n,&m)){ 64 int a,b,v; 65 M(way,inf); 66 for(int i=0;i<n;i++){ 67 scanf("%d%d%d",&a,&b,&v); 68 if(way[a][b]>v){ 69 way[a][b]=v; 70 way[b][a]=v; 71 } 72 } 73 dijkstra(1); 74 int min=inf; 75 printf("%d ",dis[m]); 76 } 77 return 0; 78 }