Cracker

Use rpsrunner.py to play unranked matches on your computer.

Source code:

import random
output = random.choice(["R", "S", "P"])
if input == "":
	history = []
	guess = ""
	x = 0
else:
	history = [input] + history
	x = 0
	while (
		(x + 1 < len(history))
		and (history[min(x, len(history) - 1)] != history[0])
	):
		x += 1
	guess = history[max(0, min(x - 1, len(history) - 1))]
if guess == "R":
	output = "P"
elif guess == "S":
	output = "R"
elif guess == "P":
	output = "S"