最短路路径还原

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define inf 100000
using namespace std;
int n, m, d[100], pre[100], dis[100][100];
bool vis[100];
int main(){
int i, j;
while(scanf("%d%d", &n, &m) == 2){
memset(vis, 0, sizeof(vis));
memset(pre, -1, sizeof(pre));
for(i = 1; i <= n; i++)
d[i] = inf;
for(i = 1; i <= n; i++)
for(j = 1; j <= n; j++)
dis[i][j] = inf;
int a, b, c;
for(i = 1; i <= m; i++){
scanf("%d%d%d", &a, &b, &c);
dis[a][b] = dis[b][a] = min(c, dis[a][b]);
}
d[1] = 0;
while(1){
int decide = -1;
for(i = 1; i <= n; i++)
if(!vis[i])
if(decide == -1 || d[i] < d[decide])
decide = i;
if(decide == -1)
break;
for(i = 1; i <= n; i++){
if(!vis[i] && i!=decide){
if(d[i] > d[decide]+dis[decide][i]){
pre[i] = decide;
d[i] = d[decide]+dis[decide][i];
}
}
}
vis[decide] = 1;
}
int pp = n;
int ans[100], tot = 0;
while(pp != -1){
ans[++tot] = pp;
pp = pre[pp];
}
for(i = tot; i >= 1; i--)
printf("%d ", ans[i]);
printf("\n");
}
return 0;
}