POJ 1734 Sightseeing trip(无向图最小环+输出路径)

题目链接

 #include <cstdio>
 #include <string>
 #include <cstring>
 #include <queue>
 #include <map>
 #include <algorithm>
 using namespace std;
 #define LL __int64
 #define MOD 1000000007
 #define INF 0xffffff
 int dp[][],g[][],pre[][];
 int ans[];
 int main()
 {
     int n,m,minz,i,j,k,sv,ev,w,num,temp;
     while(scanf("%d%d",&n,&m)!=EOF)
     {
         memset(pre,-,sizeof(pre));
         for(i = ; i <= n; i ++)
         {
             for(j = ; j <= n; j ++)
                 dp[i][j] = g[i][j] = INF;
             dp[i][i] = g[i][i] = ;
         }
         for(i = ; i <= m; i ++)
         {
             scanf("%d%d%d",&sv,&ev,&w);
             g[sv][ev] = dp[sv][ev] = min(dp[sv][ev],w);
             g[ev][sv] = dp[ev][sv] = min(dp[ev][sv],w);
             pre[sv][ev] = ev;
             pre[ev][sv] = sv;
         }
         minz = INF;
         for(i = ; i <= n; i ++)//求最小环
         {
             for(j = ; j <= i-; j ++)
                 for(k = j+; k <= i-; k ++)
                 {
                     if(minz > dp[j][k] + g[j][i] + g[i][k])
                     {
                         minz = dp[j][k] + g[j][i] + g[i][k];
                         num = ;
                         ans[] = i;
                         temp = j;
                         while(temp != -)
                         {
                             ans[num++] = temp;
                             temp = pre[temp][k];
                         }
                     }
                 }
             for(j = ; j <= n; j ++)
                 for(k = ; k <= n; k ++)
                 {
                     if(dp[j][k] > dp[j][i] + dp[i][k])
                     {
                         dp[j][k] = dp[j][i] + dp[i][k];
                         pre[j][k] = pre[j][i];
                     }
                 }
         }
         if(minz == INF)
         printf("No solution.\n");
         else
         {
             for(i = ;i < num;i ++)
             {
                 if(i == )
                 printf("%d",ans[i]);
                 else
                 printf(" %d",ans[i]);
             }
         }
         printf("\n");
     }
     return ;
 }