InternBootcamp/internbootcamp/libs/wordladder/solving/solver.py
2025-05-23 15:27:15 +08:00

70 lines
3 KiB
Python
Executable file

from libs.wordladder.solving.puzzle import Puzzle
from libs.wordladder.solving.solution import Solution, CandidateSolution
from libs.wordladder.solving.word_distance_map import WordDistanceMap
from libs.wordladder.words.word import Word
class Solver(object):
def __init__(self, puzzle: Puzzle):
self.puzzle: Puzzle = puzzle
self.start_word: Word = puzzle.start_word
self.end_word: Word = puzzle.end_word
self.explored_count: int = 0
self.solutions: list[Solution] = []
self.reversed: bool = False
self.maximum_ladder_length: int = 0
self.end_distances = None
def solve(self, maximum_ladder_length: int) -> list[Solution]:
self.maximum_ladder_length = maximum_ladder_length
self.start_word: Word = self.puzzle.start_word
self.end_word: Word = self.puzzle.end_word
self.reversed = False
self.explored_count = 0
self.solutions.clear()
diffs = self.start_word - self.end_word
if diffs == 0:
self.solutions.append(Solution(self.start_word))
return self.solutions
elif diffs == 1:
self.solutions.append(Solution(self.start_word, self.end_word))
if self.maximum_ladder_length == 2:
return self.solutions
elif self.maximum_ladder_length == 3:
self._short_circuit_ladder_length_3()
return self.solutions
elif diffs == 2 and self.maximum_ladder_length == 3:
self._short_circuit_ladder_length_3()
return self.solutions
self.reversed = len(self.start_word.linked_words) > len(self.end_word.linked_words)
if self.reversed:
self.start_word = self.puzzle.end_word
self.end_word = self.puzzle.start_word
self.end_distances = WordDistanceMap(self.end_word, self.maximum_ladder_length - 1)
for linked_word in self.start_word.linked_words:
if self.end_distances.reachable(linked_word, self.maximum_ladder_length):
self._solve(CandidateSolution(self.start_word, linked_word))
return self.solutions
def _solve(self, candidate: CandidateSolution):
self.explored_count += 1
last_word = candidate.last_word
if last_word == self.end_word:
self.solutions.append(candidate.as_solution(self.reversed))
return
if len(candidate) < self.maximum_ladder_length:
new_max = self.maximum_ladder_length - len(candidate)
for linked_word in last_word.linked_words:
if not candidate.seen(linked_word) and self.end_distances.reachable(linked_word, new_max):
self._solve(candidate.spawn(linked_word))
def _short_circuit_ladder_length_3(self):
common: set[str] = set()
for word in self.start_word.linked_words:
common.add(str(word))
for word in self.end_word.linked_words:
if str(word) in common:
self.solutions.append(Solution(self.start_word, word, self.end_word))