【HDOJ】1198 Farm Irrigation

其实就是并查集，写麻烦了，同样的代码第一次提交wa了，第二次就过了。

 #include <stdio.h>
 #include <string.h>

 #define MAXNUM 55
 #define UP    0
 #define RIGHT 1
 #define DOWN  2
 #define LEFT  3

 char buf[MAXNUM][MAXNUM];
 int bin[MAXNUM*MAXNUM];
 char visit[MAXNUM*MAXNUM][MAXNUM*MAXNUM];

 int direct[][] = {{-,},{,},{,},{,-}};
                     // A        B        C          D          E
 int pipes[][] = {{,,,},{,,,},{,,,},{,,,}, {,,,},
                     // F        G        H          I          J
                     {,,,},{,,,},{,,,},{,,,}, {,,,}, {,,,}};

 int find(int x) {
     int r = x;

     while (r != bin[r])
         r = bin[r];

     return r;
 }

 void merge(int x, int y) {
     int fx, fy;

     fx = find(x);
     fy = find(y);

     if (fx != fy)
         bin[fx] = fy;
 }

 int main() {
     int n, m;
     int i, j, k, x, y, p, q, is, id, ns, nd;

     while (scanf("%d %d%*c", &n, &m) != EOF) {
         if (m< || n<)
             break;
         for (i=; i<n; ++i)
             scanf("%s", buf[i]);
         memset(visit, , sizeof(visit));
         for (i=; i<n*m; ++i)
             bin[i] = i;
         for (i=; i<n; ++i) {
             for (j=; j<m; ++j) {
                 is = buf[i][j] - 'A';
                 ns = i*m+j;
                 for (k=; k<; ++k) {
                     x = i + direct[k][];
                     y = j + direct[k][];
                     if (x< || x>=n || y< || y>=m)
                         continue;
                     nd = x*m+y;
                     if (visit[ns][nd] || visit[nd][ns])
                         continue;
                     id = buf[x][y] - 'A';
                     switch (k) {
                     case UP:
                         p = pipes[is][UP];
                         q = pipes[id][DOWN];
                         break;
                     case RIGHT:
                         p = pipes[is][RIGHT];
                         q = pipes[id][LEFT];
                         break;
                     case DOWN:
                         p = pipes[is][DOWN];
                         q = pipes[id][UP];
                         break;
                     case LEFT:
                         p = pipes[is][LEFT];
                         q = pipes[id][RIGHT];
                         break;
                     default: ;
                     }
                     if (p && q)
                         merge(ns, nd);
                     visit[ns][nd] = ;
                     visit[nd][ns] = ;
                 }
             }
         }
         k = ;

         for (i=; i<n*m; ++i) {
             if (i == bin[i])
                 ++k;
         }
         printf("%d\n", k);
     }

     return ;
 }