Bayes3_0.995

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

Source code:

import math
import random

def action(kappa):
  p = [random.gammavariate(x+1,1) for x in kappa]
  e = [p[(i+2)%3] - p[(i+1)%3] for i in xrange(3)]
  for i in xrange(3):
    if e[i] < e[(i+1)%3] == e[(i+2)%3]:
      return random.choice([(i+1)%3,(i+2)%3])
    if e[i] <= e[(i+1)%3] < e[(i+2)%3]:
      return (i+2)%3
  return random.choice([0,1,2])

if input == '':
  stat, c, s = [[0.0 for j in xrange(3)] for i in xrange(9**2)], 0, 0
else:
  for i in xrange(9**2):
    for j in xrange(3):
      stat[i][j] *= 0.995
  c += 1
  o = { 'R': 0, 'P': 1, 'S': 2 }[input]
  if c > 2:
    stat[s][o] += 1
  s = 9 * (s % 9) + 3 * m + o
m = action(stat[s])
output = 'RPS'[m]