I have a an integer, n, that is equal to 1379. I want to create an array of all the permutations of n (1397, 1739, 1793, 1937, 1973, 3179, etc...). How would I code this?

Note: I know how many permutations exist. Call that variable "tPerms"

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- 11-30-2008, 09:59 PMmatzahboyFind all permutations of a number
I have a an integer, n, that is equal to 1379. I want to create an array of all the permutations of n (1397, 1739, 1793, 1937, 1973, 3179, etc...). How would I code this?

Note: I know how many permutations exist. Call that variable "tPerms" - 11-30-2008, 11:21 PMFubarable
At your current level, I'd bet you'd be able to solve this without our help. Why not first give it a go? Also, myself, I'd use characters or String representations of the numbers since we're not really treating these things as numbers.

- 12-01-2008, 04:50 AMEranga
- 12-01-2008, 10:45 PMmatzahboy
I found the following code (courtesy of Permutations.java). For the particular problem I'm trying to do, I need to find the 1000000th permutation. How would I modify this code to do that?

Code:`// print N! permutation of the characters of the string s (in order)`

public static void perm1(String s) { perm1("", s); }

private static void perm1(String prefix, String s) {

int N = s.length();

if (N == 0) System.out.println(prefix);

else {

for (int i = 0; i < N; i++)

perm1(prefix + s.charAt(i), s.substring(0, i) + s.substring(i+1, N));

}

}

- 12-02-2008, 12:35 AMCJSLMANhhhmmm...
- Do you know what that piece of code does?
- Do you know what the "prefix" and "s" variables are? What they represent?

CJSL - 12-02-2008, 03:00 AMemceenugget
I don't understand what the 1 millionth (or nth) permutation means. There is no order to permutations.

- 12-02-2008, 03:59 AMmatzahboy
I'm basically trying to solve problem 24 of project euler (Problem 24 - Project Euler)