【HDOJ】1619 Unidirectional TSP

题目本身一点儿都不难，但是就是被字典序搞死了。写的挺麻烦，但是过了，逆向做好做一点儿。

 /* 1619 */
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>

 #define MAXN 15
 #define MAXM 105
 #define INF    9999999

 int dp[MAXN][MAXM];
 int path[MAXN][MAXM];
 int map[MAXN][MAXM];
 int stack[MAXM], top;
 int d[];
 int ans;
 int n, m;

 void solve(int beg) {
     int i, j, k, tmp;

     for (i=; i<n; ++i)
         dp[i][m-] = INF;
     dp[beg][m-] = map[beg][m-];
     path[beg][m-] = -;

     for (j=m-; j>=; --j) {
         for (i=; i<n; ++i) {
             if (i == )
                 d[] = n - ;
             else
                 d[] = i - ;
             d[] = i;
             if (i == n-)
                 d[] = ;
             else
                 d[] = i + ;
             if (dp[d[]][j+] == dp[d[]][j+]) {
                 k = d[]<d[] ? d[]:d[];
                 if (dp[k][j+] == dp[d[]][j+])
                     k = k<d[] ? k:d[];
                 else if (dp[k][j+] < dp[d[]][j+])
                     k = k;
                 else
                     k = d[];
             } else if (dp[d[]][j+] < dp[d[]][j+]) {
                 if (dp[d[]][j+] == dp[d[]][j+])
                     k = d[]<d[] ? d[]:d[];
                 else if (dp[d[]][j+] < dp[d[]][j+])
                     k = d[];
                 else
                     k = d[];
             } else {
                 if (dp[d[]][j+] == dp[d[]][j+])
                     k = d[]<d[] ? d[]:d[];
                 else if (dp[d[]][j+] < dp[d[]][j+])
                     k = d[];
                 else
                     k = d[];
             }
             path[i][j] = k;
             dp[i][j] = dp[k][j+];
             if (dp[i][j] != INF)
                 dp[i][j] += map[i][j];
         }
     }

     tmp = INF;
     for (i=; i<n; ++i) {
         if (dp[i][] < tmp) {
             tmp = dp[i][];
             k = i;
         }
     }

     if (tmp < ans) {
         ans = tmp;
         top = ;
         j = ;
         stack[top++] = k + ;
         while (path[k][j] >= ) {
             stack[top++] = path[k][j] + ;
             k = path[k][j];
             ++j;
         }
     }
 }

 int main() {
     int i, j, k, tmp;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     while (scanf("%d %d", &n, &m) != EOF) {
         for (i=; i<n; ++i)
             for (j=; j<m; ++j)
                 scanf("%d", &map[i][j]);
         ans = INF;
         for (i=; i<n; ++i)
             solve(i);

         for (i=; i<m-; ++i)
             printf("%d ", stack[i]);
         printf("%d\n", stack[m-]);
         printf("%d\n", ans);
     }

     return ;
 }