# Recursive Ideals

1. Feb 4, 2005

Hello all

What is the difference between merge sort, selection sert,binary search , linear search and insertion sort? Also if you are given a recursive method, is there an easy way without tracing the method to find how many calls you need to make? For example:

Code (Text):

public int A(int a, int b )
{
if ( a< 0 )
return (b);
else if  (b < 1)
return (a);
else
return(A(a-2, b-4) + A(a-1, b-2));
}

I know that you work from the left to the right. Could you somehow use the formula $$2^{k} - 1$$?

Thanks a lot guys

2. Feb 4, 2005

any ideas?

thanks

3. Feb 4, 2005

### christinono

I personally HATE recursion of all types, mainly because it is so hard to implement and to trace. I don't think there is an easier way to find out how many calls it needs to make other than tracing the program. Since each case is different, the function will have to call itself different numbers of times. All of the sorting methods I know are bubble sort, insertion sort and quick sort. Insertion sort doesn't use recursion. It simply consists of searching through the list (could be an array, for example) for the smallest number (using for loops and if statements) and copying that number in a new array. You do this until the new array contains the numbers in order. Then, you copy the values from the nuw array to the original array. Hope this helps...