As with other isolated teachings like Matt. 5-7, let's again note Marcan and Lucan parallels:

• Matthew 12:38 Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee.
• 39 But he answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas:
• 40 For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.
• 41 The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.
• 42 The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here. (Luke 11:29-31, Mark 8:11-12)
• 43 When the unclean spirit is gone out of a man, he walketh through dry places, seeking rest, and findeth none.
• 44 Then he saith, I will return into my house from whence I came out; and when he is come, he findeth it empty, swept, and garnished.
• 45 Then goeth he, and taketh with himself seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is worse than the first. Even so shall it be also unto this wicked generation. (Luke 11:24-26)

Here Matthew has obviously combined the two episodes recorded separately in Mark and Luke to make one new pericope. There is nothing here barring Matthean priority and rearrangement of a common oral tradition topically. See more discussion here.