Kenneth Rosen Edition 7 Exercise 6.6 Question 12 (Page No. 438)

Question

Develop an algorithm for generating the $r$-permutations of a set of $n$ elements.

Answer 1

1. Let us take two variables r and n (r<=n)

2. Permutation (n,r)

3.for (I=n,i<=n-r+1,i--)

 do n*r

4.sum of all these products

5.final answer.//    ( I am not sure , I require help)