【HDOJ】1484 Basic wall maze

BFS。

 /* 1484 */
 #include <iostream>
 #include <queue>
 #include <string>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;

 typedef struct {
     int x, y;
     string s;
 } node_t;

 bool m[][][];
 bool visit[][];
 char ds[] = "NSWE";
 int dir[][] = {
     -,,,,,-,,
 };

 const int n = ;
 int bx, by, ex, ey;
 string ans;

 void bfs() {
     int x = bx, y = by;
     int i, j, k;
     queue<node_t> Q;
     string s;
     node_t nd, tmp;

     memset(visit, false, sizeof(visit));
     visit[x][y] = true;
     nd.x = x;
     nd.y = y;
     nd.s = "";
     Q.push(nd);

     while (!Q.empty()) {
         nd = Q.front();
         Q.pop();
         for (i=; i<; ++i) {
             if (m[nd.x][nd.y][i])
                 continue;
             x = nd.x + dir[i][];
             y = nd.y + dir[i][];
             if (x<= || x> || y<= || y> || visit[x][y])
                 continue;
             visit[x][y] = true;
             tmp.x = x;
             tmp.y = y;
             tmp.s = nd.s + ds[i];
             if (x==ex && y==ey) {
                 ans = tmp.s;
                 return ;
             }
             Q.push(tmp);
         }
     }
 }

 int main() {
     int i, j, k;
     int x, y;
     int a, b, c, d;

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

     while (scanf("%d %d",&by,&bx)!=EOF && (by||bx)) {
         scanf("%d %d", &ey, &ex);
         memset(m, false, sizeof(m));
         for (i=; i<; ++i) {
             scanf("%d%d%d%d", &a,&b,&c,&d);
             if (b == d) {
                 // north & south need to mask
                 for (y=a+; y<=c; ++y) {
                     m[b][y][] = true;
                     m[b+][y][] = true;
                 }
             } else {
                 // west & east need to mask
                 for (x=b+; x<=d; ++x) {
                     m[x][a][] = true;
                     m[x][a+][] = true;
                 }
             }
         }
         bfs();
         printf("%s\n", ans.c_str());
     }

     return ;
 }