Non-repetitive random seek in a range Algorithm

Question

I\'m looking for an efficient algorithm that produces random values within a range, without repetitions.

In pseudo-code: (in class Rand)

  Rand(long from         


        

Answer 1

You could proceed this way (in python):

Create a xrange and pick k random element from it and use it as a RanndomGenerator:

import random

def randomFromTo(FROM,TO,k): #k is the number of sample you want to generate
    m= random.sample(xrange(FROM,TO),k)
    return (i for i in m)

Your Generator will generate all number randomly from FROM to TO and fail when it has generated more than k numbers:

with this example you would get :

RandomGenerator=randomFromTo(10,1000000000,12)

for k in range(12): 
    print RandomGenerator.next()

you get

57625960
50621599
2891457
56292598
54608718
45258991
24112743
55282480
28873528
1120483
56876700
98173231