BFS Meets Binary Search

xxxxxxxxx xxx_xxxxxxxx_xxxxxxx(xxxx), xxxxx xxxxx xxx xxxxxx xxxxxxx xxxxxxx xxxx xxxxx xxxx x xxxxx xxxxx x xxxx xx xxxxx xxxx xxx xxx-xxxx xx xxx xxxxxx-xxxxx.

x xxxxxxxxxx xxxxxxxx xxxxx xxx x xxxxxxx xxx xx xxx xxxxxx: x xxxxxxxxxxx xxxx xx xxxxx xxxxx xxxx xxxx xxxxxxx x xxxxxxx xxxxx, xx xxxxxxx xxxx x (xxxx xxxxx) xx xxxxxx (xxxxxxx xxxxxx). xxxx xxxxx xxxx xxxxxx xx xxx xxx-xxxx xxxx xxx xxxx xxxxx xxx xxxxxxxx xxxxxx xx xxx xxxxxx-xxxxx xxxx, xxxxxx xxxx xxxxxxx xxxxxxxxxxxx xx xxxxxxxxxx xxxxxxxx xxxxx. x xxxxx xx xxxx xx xxxx xx xxx xxxxx xxx: xxx xxxx xxxxx xxxxx xxx xxxxxxx xxxxxxx xxxxx xxx xxxxxxx xxxx (xxxxxxxxx xxx xxx xxxxxxxxx) xxxxxx xx xxx xxxx.

xxx xxxxx xxxx xx x xxxxxxxxx xx xxxxxxxx xxxx x xx xxxxxx, xxxxx xx xxxxx-xxxxxx xxxx. xxxxxx xxx xxxxxxxx xxxxxxx (x) xxxx xxxx xxxx xxxx xxxx xxx-xxxx xx xxxxxx-xxxxx xxxx xxxx xxxxx xxxx xxxxxxx xxxxx xx xxxx (x).

xxx xxx_xxxxxxxx_xxxxxxx(xxxx: xxxx[xxxx[xxx]]) -> xxx: ...

xxxxxxxx

xxx_xxxxxxxx_xxxxxxx([[xx, xxxx], [xxxxx, xx]])
# xxxx  (xxxxx xx -> xxxx -> xx xxxxx xxxxxxx xxxx; xxxxxxxxx xxxxxxx xxxxx xxxxx xxxx xxxxx)

xxx_xxxxxxxx_xxxxxxx([[xxx, xxx, xxxxx], [xxx, xxxxx, xxx], [xxxxx, xxx, xxx]])
# xxxxx  (xxxxx xxxxx xx xxx xxx xxxxxx xx xxxxxx xxxxxxx xxxxx xx xxxxx)

xxxxxxxxxxx

• xxxx xxxxxxxxxx xx xx (xxx xxxxx xxx); xxxxx xxxx xx xx xxxxxxx xxxx x xx xxxxxx, xx xx xxxxxx xxxxxx xxxxxx ((x = xxxxxx) xxxxxx xxxxx xxxx).
• x xxxxxx-xxxx xxxx xxxxxxx xxx xxx xxxxx.
• xxxxxx xxxxx xxxxxxxxx (x) xx xxxx, xxxx x xxxx xxxxx xxxx xxx xxxx, xx xxx xxxx xx xxx xxxxxxx xxxxxx xxxxx.
• xxxxxxxxxxx xxxxx xx xxxxxxxxxxx xxx xxxx xxx xxxxxx xx xxx xxxxxxx xxxxxx xxxx. xxxxxx xxxxxxx xxxx "xx xxxxx x xxxx xxxxx xxxx xxxxx (xx x)" xx x xxx/xx xxxxxxxx xxxx xxxx xxxx xxxxxx xx (x) xxxxx.