dfs寻路算法---迷宫问题实现

#include<stdio.h>
#include<string.h>
#define MAXN 105
int n, m, xs, ys, xt, yt;
int vis[MAXN][MAXN], fa[MAXN][MAXN], dist[MAXN][MAXN], last_dir[MAXN][MAXN], num[MAXN][MAXN];
int maze[MAXN][MAXN] = {{1,1,0,1,1},{1,0,1,1,1},{1,0,1,0,0},{1,0,1,1,1},{1,1,1,0,1},{1,1,1,1,1}};
int dx[] = {-1,1,0,0};
int dy[] = {0,0,-1,1};
char name[] = "UDLR";

int q[MAXN*MAXN];
void bfs(int x, int y) {
int front=0, rear=0, d, u;
u = x*m+y;
vis[x][y] = 1; fa[x][y] = u; dist[x][y] = 0;
q[rear++] = u;
while(front<rear) {
u = q[front++];
x = u/m; y = u%m;
for(d = 0; d < 4; d++) {
int nx = x+dx[d], ny = y+dy[d];
if(nx>=0 && nx<n && ny>=0 && ny<m && maze[nx][ny] && !vis[nx][ny]) {
int v = nx*m+ny;
q[rear++] = v;
vis[nx][ny] = 1;
fa[nx][ny] = u;
dist[nx][ny] = dist[x][y]+1;
last_dir[nx][ny] = d;
}
}
}
}

void print_path(int x, int y) {
int fx = fa[x][y]/m;
int fy = fa[x][y]%m;
if(fx != x || fy != y) {
print_path(fx, fy);
putchar(name[last_dir[x][y]]);
}
}

int dir[MAXN*MAXN];
void print_path2(int x, int y) {
int c = 0;
for(;;) {
int fx = fa[x][y]/m;
int fy = fa[x][y]%m;
if(fx == x && fy == y) break;
dir[c++] = last_dir[x][y];
x = fx;
y = fy;
}
while(c--)
putchar(name[dir[c]]);
}

int main() {
//int i, j;
n = 6;
m = 5;
xs = 0;
ys = 0;
xt = 0;
yt = 4;
//scanf("%d%d%d%d%d%d", &n, &m, &xs, &ys, &xt, &yt);
//   for(i = 0; i < n; i++)
//     for(j = 0; j < m; j++)
//       scanf("%d", &maze[i][j]);
memset(vis, 0, sizeof(vis));
bfs(xs, ys);
print_path(xt, yt);
putchar('\n');
print_path2(xt, yt);
putchar('\n');
return 0;
}