Code for Variations with repetition (combinatorics) using javascript?

Question

Does anyone have Javascript code for generating all variations with repetition?

Example of variations with repetition:

(size=3, input=A,B)
AAA, AAB, ABA, BAA, ABB, BAB, BBA, BBB

What I need is to do something similar for numbers from 0-9 as the input and 6 digits length as size (according to my example).

Just to know, I got this working with a code in Java and also in .NET based on this project (check the link). All variations with repetition for what I need generates 1000000 values.

http://www.codeproject.com/KB/recipes/Combinatorics.aspx

Is it possible to do it in Javascript?

Thanks in advance.

Answer 1

you have chosen the simplest case from combinatorics...

var i, n = 1000000;
for (i = 0; i < n; i++)
  console.log(('' + (i + n)).substring(1));

will give you all the combinations of 0-9 in 6 spots (1000000 === Math.pow(10, 6)).

Answer 2

I've just wrote it right now, it needs probably more tests and optimizations but this should get you started:

​var input = "ABCD";
var size = 3;
var results = [];

function solve(i, elt) {
    if(elt.length == size) { 
       results.push(elt);
       return;        
    }
    for(var j = 0; j < input.length; j++) {
       solve(j, elt+input[j]);
    }        
}​​​​​​

solve(0, "");
​console​.log(results);​