【ABC453 D】Go Straight 復習メモ：BFSの状態管理とTLE対策

A problem with a large state space caused a Time Limit Exceeded (TLE) error. To fix this, the code was modified to use a 3D array instead of a set to manage states, resulting in a significant speedup. This change allowed the code to pass the test. The key takeaway is to use a data structure with fast indexing, such as a 3D array, when dealing with large state spaces.