【动态规划】[UVA1025]A Spy in the Metro 城市里的间谍

参考：https://blog.csdn.net/NOIAu/article/details/71517440

https://blog.csdn.net/c20180630/article/details/75245665

https://blog.csdn.net/rechard_chen/article/details/41357173

https://blog.csdn.net/acvay/article/details/43565183

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 using namespace std;
 const int N=;
 const int M=;
 const int INF=1e8;
 int n,t,l,r,kcase;//n车站数，t时间，l向右车辆数，kcase样例数
 int station_time[N];//车站之间的时间
 int have_train[M][N][],dp[M][N];
 void test()
 {
     cout<<'n'<<n<<'t'<<t<<endl;
     for (int i=;i<n;i++)
     {
         cout<<station_time[i]<<' ';
     }
     cout<<endl;
     for (int i=;i<=t;i++)
     {
         for (int j=;j<=n;j++)
         {
             printf("[%9d]",dp[i][j]);
         }
         printf("\n");
     }
     getchar();
 }
 void init()
 {
     cin>>t;
     memset(station_time,,sizeof(station_time));
     for (int i=;i<n-;i++)
     {
         cin>>station_time[i];
     }
     cin>>r;
     memset(have_train,,sizeof(have_train));
     while (r--)
     {
         int d;
         cin>>d;
         for (int j=;j<n;j++)
         {
             if (d<=t)
             {
                 have_train[d][j][]=;
             }
             d+=station_time[j-];
         }
     }
     cin>>l;
     while (l--)
     {
         int d;
         cin>>d;
         for (int j=n;j>;j--)
         {
             if (d<=t)
             {
                 have_train[d][j][]=;
             }
             d+=station_time[j-];
         }
     }
 }
 void dpp()
 {
     memset(dp,,sizeof(dp));
     for (int j=;j<=n;j++)
     {
         dp[t][j]=INF;
     }
     dp[t][n]=;
     for (int i=t-;i>=;i--)//注意i>=0!
     {
         for (int j=;j<=n;j++)
         {
             dp[i][j]=dp[i+][j]+;
             if (j<n&&have_train[i][j][]&&i+station_time[j-]<=t)
             {
                 dp[i][j]=min(dp[i][j],dp[i+station_time[j-]][j+]);
             }
             if (j>&&have_train[i][j][]&&i+station_time[j-]<=t)//注意判断条件不要写错！
             {
                 dp[i][j]=min(dp[i][j],dp[i+station_time[j-]][j-]);
             }
         }

     }
 //    test();
     cout<<"Case Number "<<kcase++<<": ";
     if (dp[][]>=INF)
     {
         cout<<"impossible"<<endl;
     }
     else
     {
         cout<<dp[][]<<endl;
     }
 }
 int main()
 {
     kcase=;
 //    freopen("btext.txt","r",stdin);
     while (cin>>n&&n)
     {
         init();
         dpp();
     }

     return ;
 }