Socks - Pair Matching

README.md

Full writeup:

http://blog.samsandberg.com/2014/11/03/socks-pair-matching/

Usage:

$ python socks.py 3 -n 100000
3 pairs of socks
100000 iterations
{False: 60011, True: 39989}
Good 39.99% of the time 

socks.py

import argparse
import random

def iteration(num_pairs):
    socks = []
    for i in xrange(num_pairs):
        # 0 and 1 representing R and L socks
        socks += [0, 1]
    random.shuffle(socks)
    for i in xrange(num_pairs):
        # Sums of each two consecutive socks should be 1 (0 + 1)
        if sum(socks[i*2:i*2+2]) != 1:
            return False
    return True

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('num_pairs', type=int)
    parser.add_argument('-n', '--num_iterations', type=int, default=1)
    args = parser.parse_args()
    results = {
        True: 0,
        False: 0,
    }
    for i in xrange(args.num_iterations):
        results[iteration(args.num_pairs)] += 1
    print "%s pairs of socks" % args.num_pairs
    print "%s iterations" % args.num_iterations
    print results
    print "Good %0.2f%% of the time " % (100.0 * results[True] / args.num_iterations)

main()