Recursion

    private static int fib(int n) {
        if (n <= 2) return 1;
        return fib (n-1) + fib(n-2);
    }

int ack(int m, int n)
{
        if (!m) return n + 1;
        if (!n) return ack(m - 1, 1);
        return ack(m - 1, ack(m, n - 1));
}

cmon guys

      private static HashSet<String> combinations(String s, int c) {
        HashSet<String> combs = new HashSet<String>();
        if(s.equals("")) {
            return null;
        } else if(s.length() == c) {
            combs.add(s);
            return combs;
        }
        for(int i = 0; i < s.length(); i++) {
            combs.addAll(combinations(s.substring(0, i) + s.substring(i+1), c));
        }
        return combs;
    }
    
    private static HashSet<String> permutations(String s, String prefix) {
        HashSet<String> perms = new HashSet<String>();
        if(s.length() == 0) {
            perms.add(prefix);
            return perms;
        }
        for(int i = 0; i < s.length(); i++) {
            perms.addAll(permutations(s.substring(0,i) + s.substring(i+1), prefix + s.charAt(i))); 
        }
        return perms;
    }

>>57494502
implying half of gee could even write a recursive function

here's a nice way to reverse a LL.

public ListNode reverseList(ListNode head) {
    return reverseListUtil(head, null);
}

private ListNode reverseListUtil(ListNode root, ListNode prev) {
    if (root == null) return prev;
    
    ListNode temp = root.next;
    root.next = prev;
    return reverseListUtil(temp, root);
}

File: IMG_20161022_110340.jpg (28KB, 302x389px) Image search: [Google]

28KB, 302x389px

>>57494394
>>57494430
>>57494502
>not tail recursive

File: Fibonachi.gif (2KB, 174x47px) Image search: [Google]

2KB, 174x47px

>>57494430
Not using this

>>57494626
Here you are

let pow a b =
  let rec loop accu a = function
    | 0 -> accu
    | b ->
      let accu =
        if b mod 2 = 0 then
          accu
        else
          a * accu in
      loop accu (a * a) (b / 2) in
  loop 1 a b
;;

>>57494394

public static bool rec() {
    if(Math.random() < 0.0005) {
        return true;
    }
    return rec();
}

Will this code halt?
If it halts what will it return?

I can never think recursively.

>>57497755
I think it will go to a loop for ever because I am pretty sure that Math.random() generates integers which you are comparing it to a different data type

>>57494394
int willy()
{
return willy() + 1;
}

>>57499009
>Math.random() generates integers


>public static double random()

>Returns a double value with a positive sign, greater than or equal to 0.0 and less than 1.0. Returned values are chosen pseudorandomly with (approximately) uniform distribution from that range.