Word ladder
= Word ladder
A <search problem> whose states are words of fixed length, with a transition changing exactly one letter and requiring the resulting word to belong to a specified dictionary. Unit <path costs> make a shortest <graph path> a minimum-mutation solution. <Hamming distance> to the target is a <consistent heuristic>: one transition changes this distance by at most one. Dictionary restrictions may force a longer solution or make the target unreachable.