| Author | KendallHopkins | 
| Submission date | 2011-06-09 07:20:27.771288 | 
| Rating | 2836 | 
| Matches played | 5314 | 
| Win rate | 27.42 | 
Use rpsrunner.py to play unranked matches on your computer.
import random
lose = 2
win = 1
tie = 0
unknown = -1
rpc = ['R','P','S']
if not input:
    game_outcome = unknown
    grid = [[0,0,0],[0,0,0],[0,0,0]]
    output = random.choice(rpc)
else:
    if game_outcome != unknown:
        grid[game_outcome][(rpc.index( last_input )-rpc.index( input ))%3] += 1
    
    game_outcome = (rpc.index( input ) - rpc.index( output )) % 3
    last_input = input
    
    if grid[game_outcome][0] > grid[game_outcome][1]:
        if grid[game_outcome][0] > grid[game_outcome][2]:
            output = rpc[(rpc.index( input )-game_outcome+1)%3]
        else:
            output = rpc[(rpc.index( input )-game_outcome)%3]
    else:
        if grid[game_outcome][1] > grid[game_outcome][2]:
            output = rpc[(rpc.index( input )-game_outcome+2)%3]
        else:
            output = rpc[(rpc.index( input )-game_outcome)%3]