1 #include<stdio.h>
2 #define max 100000000;
3 int main()
4 {
5 int n,m,i,j,k,min,a,b,c,hash[1005],ar[1005],length[105][105];
6 while (~scanf("%d%d",&n,&m)&&(n!=0||m!=0))
7 {
8 for (i=1;i<=n;i++)
9 for (j=1;j<=n;j++) length[i][j]=max;
10 for (i=1;i<=m;i++)
11 {scanf("%d%d%d",&a,&b,&c); length[a][b]=length[b][a]=c; }
12 for (i=1;i<=n;i++) {ar[i]=length[1][i]; hash[i]=0; }
13 for (i=1;i<n;i++)
14 {
15 min=max;
16 for (j=1;j<=n;j++)
17 if ((hash[j]==0)&&(ar[j]<min)) {k=j; min=ar[j]; }
18 hash[k]=1;
19 for (j=1;j<=n;j++)
20 if (min+length[k][j]<ar[j]) ar[j]=min+length[k][j];
21 }
22 printf("%d\n",ar[n]);
23 }
24
25
26
27 return(0);
28 }
