这不是一个简单的问题，因为正如 ruakh 所建议的，给定消息有许多可行的句子。例如，“JACK AND JILL WENT UP THE HILL”与“JACK AND JILL WALK CHISELED”具有相同的编码。由于这些都是语法句子并且每个单词中的单词都很常见，因此在不深入研究自然语言的情况下如何选择一个或另一个（或任何其他 40141055989476564163599 个与此消息具有相同编码的不同英语单词序列中的任何其他序列）并不明显处理。
无论如何，这里有一个动态编程解决方案来解决寻找最短句子的问题（如果出现平局，则使用最少的字符）。它还可以计算与给定消息具有相同编码的句子总数。它需要一个文件中的英语单词词典。
下一个增强功能应该是更好地衡量一个句子的可能性：也许是词频、莫尔斯语的误报率（例如，“I”是一个常见词，但它经常作为其他莫尔斯语序列的一部分出现代码序列）。棘手的部分是制定一个好的分数函数，该函数可以用动态规划计算的方式表示。
MORSE = dict(zip('ABCDEFGHIJKLMNOPQRSTUVWXYZ', [
'.-', '-...', '-.-.', '-..', '.', '..-.', '--.', '....',
'..', '.---', '-.-', '.-..', '--', '-.', '---', '.--.',
'--.-', '.-.', '...', '-', '..-', '...-', '.--', '-..-',
'-.--', '--..'
]))
# Read a file containing A-Z only English words, one per line.
WORDS = set(word.strip().upper() for word in open('dict.en').readlines())
# A set of all possible prefixes of English words.
PREFIXES = set(word[:j+1] for word in WORDS for j in xrange(len(word)))
def translate(msg, c_sep=' ', w_sep=' / '):
"""Turn a message (all-caps space-separated words) into morse code."""
return w_sep.join(c_sep.join(MORSE[c] for c in word)
for word in msg.split(' '))
def encode(msg):
"""Turn a message into timing-less morse code."""
return translate(msg, '', '')
def c_trans(morse):
"""Construct a map of char transitions.
The return value is a dict, mapping indexes into the morse code stream
to a dict of possible characters at that location to where they would go
in the stream. Transitions that lead to dead-ends are omitted.
"""
result = [{} for i in xrange(len(morse))]
for i_ in xrange(len(morse)):
i = len(morse) - i_ - 1
for c, m in MORSE.iteritems():
if i + len(m) < len(morse) and not result[i + len(m)]:
continue
if morse[i:i+len(m)] != m: continue
result[i][c] = i + len(m)
return result
def find_words(ctr, i, prefix=''):
"""Find all legal words starting from position i.
We generate all possible words starting from position i in the
morse code stream, assuming we already have the given prefix.
ctr is a char transition dict, as produced by c_trans.
"""
if prefix in WORDS:
yield prefix, i
if i == len(ctr): return
for c, j in ctr[i].iteritems():
if prefix + c in PREFIXES:
for w, j2 in find_words(ctr, j, prefix + c):
yield w, j2
def w_trans(ctr):
"""Like c_trans, but produce a word transition map."""
result = [{} for i in xrange(len(ctr))]
for i_ in xrange(len(ctr)):
i = len(ctr) - i_ - 1
for w, j in find_words(ctr, i):
if j < len(result) and not result[j]:
continue
result[i][w] = j
return result
def shortest_sentence(wt):
"""Given a word transition map, find the shortest possible sentence.
We find the sentence that uses the entire morse code stream, and has
the fewest number of words. If there are multiple sentences that
satisfy this, we return the one that uses the smallest number of
characters.
"""
result = [-1 for _ in xrange(len(wt))] + [0]
words = [None] * len(wt)
for i_ in xrange(len(wt)):
i = len(wt) - i_ - 1
for w, j in wt[i].iteritems():
if result[j] == -1: continue
if result[i] == -1 or result[j] + 1 + len(w) / 30.0 < result[i]:
result[i] = result[j] + 1 + len(w) / 30.0
words[i] = w
i = 0
result = []
while i < len(wt):
result.append(words[i])
i = wt[i][words[i]]
return result
def sentence_count(wt):
result = [0] * len(wt) + [1]
for i_ in xrange(len(wt)):
i = len(wt) - i_ - 1
for j in wt[i].itervalues():
result[i] += result[j]
return result[0]
msg = 'JACK AND JILL WENT UP THE HILL'
print sentence_count(w_trans(c_trans(encode(msg))))
print shortest_sentence(w_trans(c_trans(encode(msg))))