int alt = dist[u.y][u.x] + get_grid(v->key.x, v->key.y);
if (alt < dist[v->key.y][v->key.x]) {
dist[v->key.y][v->key.x] = alt;
int alt = dist[u.y][u.x] + get_grid(v->key.x, v->key.y);
if (alt < dist[v->key.y][v->key.x]) {
dist[v->key.y][v->key.x] = alt;