Hamlet, at several points in the play, considers his mother's sexual activity with Claudius in a way that seems to be extreme. This fits the definition of a young man with an Oedipal complex - one who feels a strong attachment to his mother and who feels in competition with the father for the mother's affection.
In Hamlet's first soliloquy in Act I scene ii, Hamlet comments upon his mother's recent remarriage by referring to sex, not something many teenage men choose to dwell upon: "O, most wicked speed, to post
With such dexterity to incestuous sheets!"
Later, when Hamlet meets with his mother in her room, he brings up her sex drive, also an unusual topic for a mother/son discussion:
Ha! have you eyes?
You cannot call it love; for at your age
The hey-day in the blood is tame, it's humble, (III.iv)
Later in the same scene, he becomes enraged at the thought of her sexual activity, screaming
Nay, but to live
In the rank sweat of an enseamed bed,
Stew'd in corruption, honeying and making love
Over the nasty sty,--
He finally concludes this odd encounter by asking his mom to refuse her husband's sexual advances. He urges her
Not this, by no means, that I bid you do:
Let the bloat king tempt you again to bed;
This is evidence that Hamlet has unusual sexual fixations on his mother, which does lend itself to an Oedipal interpretation.