Perform an exhaustive search for a binary (n,k,q) code; see http://math.stackexchange.com/questions/314645.

Question314645.java

public class Question314645 {
    static int n,k,q;

    static int [] bitCounts;

    public static void main (String [] args) {
        n = Integer.parseInt (args [0]);
        k = Integer.parseInt (args [1]);
        q = Integer.parseInt (args [2]);

        bitCounts = new int [1 << n];

        for (int i = 0;i < bitCounts.length;i++)
            for (int j = 0;j < n;j++)
                if ((i & (1 << j)) != 0)
                    bitCounts [i]++;

        recurse (new int [k],1);
    }

    static void recurse (int [] code,int index) {
        if (index == k) {
            for (int word : code) {
                System.out.print ("    ");
                for (int i = 0;i < n;i++)
                    System.out.print ((word >> i) & 1);
                System.out.println ();
            }
            System.exit (0);
        }
        
        outer:
        for (code [index] = code [index - 1] + 1;code [index] < 1 << n;code [index]++) {
            for (int i = 0;i < index;i++)
                if (bitCounts [code [i] ^ code [index]] < q)
                    continue outer;
            recurse (code,index + 1);
        }
    }
}