For each test case, print a line containing the case number (starting with 1) and an integer representing the total waiting time in the stations for a best schedule, or the word ‘impossible’ in case Maria is unable to make the appointment. Use the format of the sample output.

 

 #include <bits/stdc++.h>

 using namespace std;

 const int maxt =  + , maxn =  + ;

 const int INF = 0x3f3f3f3f;

 int read() {

     int q = ; char ch = ' ';

     while (ch<'' || ch>'') ch = getchar();

     while ('' <= ch && ch <= '') {

         q = q *  + ch - '';

         ch = getchar();

     }

     return q;

 }

 int n, t, m1, m2;

 int ti[maxn];

 int dp[maxt][maxn];

 bool have_train[maxt][maxn][];

 void init() {

     memset(have_train, false, sizeof(have_train));

     for (int i = ; i <= n - ; i++) {

         dp[t][i] = INF;

     }

     dp[t][n] = ;

 }

 int T = ;

 int main()

 {

     //freopen("input.txt", "r", stdin);

     while (scanf("%d", &n) && n) {

         t = read();

         init();

         for (int i = ; i < n; i++) {

             ti[i] = read();

         }

         ti[n] = ti[] = INF;

         m1 = read();

         int d;

         for (int i = ; i < m1; i++) {

             d = read();

             int cnt = ;

             for (int j = ; j <= n; j++) {

                 have_train[d][cnt][] = true;

                 //printf("d:%d cnt:%d\n", d, cnt);

                 cnt++;

                 d += ti[j];

             }

         }

         //printf("\n");

         m2 = read();

         for (int i = ; i < m2; i++) {

             d = read();

             int cnt = n;

             for (int j = n; j >= ; j--) {

                 have_train[d][cnt][] = true;

                 //printf("d:%d cnt:%d\n", d, cnt);

                 cnt--;

                 d += ti[j - ];

             }

         }

         for (int i = t - ; i >= ; i--) {

             for (int j = ; j <= n; j++) {

                 dp[i][j] = dp[i + ][j] + ;

                 if (i + ti[j] <= t && have_train[i][j][]) {

                     dp[i][j] = min(dp[i][j], dp[i + ti[j]][j + ]);

                 }

                 if (i + ti[j - ] <= t && have_train[i][j][]) {

                     dp[i][j] = min(dp[i][j], dp[i + ti[j - ]][j - ]);

                 }

             }

         }

         printf("Case Number %d: ", T++);

         if (dp[][] >= INF) {

             printf("impossible\n");

         }

         else {

             printf("%d\n", dp[][]);

         }

     }

     return ;

 }