gistfile1.py

import random

# Generate n random numbers in the range start...end (inclusive) with no duplicates

# end-start must by a power of 2 minus 1 (so that we can keep on dividing into 2 without accounting for off by ones)
def rnd(start, end, n):
    mid = (end-start)/2+start
    assert end >= start
    if n == 0:
        return
    # print "!", end-start
    # print start, end, mid, n
    if n > end-start:
        for number in range(start,end+1):
            yield number
        return
    # print (max(0, n-mid),min(n,mid))
    in_first = random.randint(max(0, n-(mid+1)),min(n,mid+1))
    # print in_first
    for number in rnd(start, mid, in_first):
        yield number
    for number in rnd(mid+1, end, n-in_first):
        yield number

def naive(start, end, n):
    seen = set()
    for i in range(n):
        while True:
            x = random.randint(start, end)
            if x not in seen:
                seen.add(x)
                yield x
                break
                

r =  list(rnd(0, pow(2,64)-1, 10))
print len(r)
print r

# print list(sorted(naive(0, 128-1, 10)))