Split N into X uniformly-distributed pieces

split.py

#!/usr/bin/python2.7
import sys
from random import randrange


def split(n, numPieces):
	rtn = []

	for i in range(numPieces):
		# get a good starting position to deviate from
		mid = n // numPieces

		if i % 2 == 0:
			# only get a new random delta every other iteration
			delta = randrange(0, mid)
		else:
			delta = -delta

		# if odd, dont change the last number in the set
		if numPieces % 2 != 0 and i == numPieces - 1:
			delta = 0

		rtn.append(mid + delta)
	
	numSum = sum(rtn)
	
	# remainders?
	if (numSum > n):
		diff = n - numSum
	else:
		diff = numSum - n

	# now distribute the remainder back into the set, if necessary
	if diff != 0:
		for i in range(0, abs(diff)):
			# get a random index
			index = randrange(0, numPieces)

			if diff > 0: # negative
				rtn[index] = rtn[index] - 1
			else: # positive
				rtn[index] = rtn[index] + 1

	print "sum: %d" % sum(rtn)
	return rtn	

print split(int(sys.argv[1]), int(sys.argv[2]))