/in/foo.cc: In function 'int BFS(Point)':
/in/foo.cc:28:101: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if (next.pos >= 0 && next.pos < len && a[next.pos] != ' ' && !vis[next.pos] && (i != 3 || i == 3 && now.x))
                                                                                              ~~~~~~~^~~~~~~~