Don’t worry quite so much about the stack. There is nothing fundamental that says function calls have to be implemented using stack frames; that is merely one possible technique for implementing them. Even when you have “the stack”, there’s certainly nothing that says the stack has to be limited to a small fraction of available … Read more
The canonical way to do recursion with pure lambda expressions is to use a fixpoint combinator, which is a function with the property fixpoint f x = f (fixpoint f) x If we assume that such a combinator exists, we can write the recursive function as factorial = fixpoint (\ff n -> if n == … Read more
Here’s another way: (defn factorial [n] (reduce * (range 1 (inc n)))) This won’t blow the stack because range returns a lazy seq, and reduce walks across the seq without holding onto the head. reduce makes use of chunked seqs if it can, so this can actually perform better than using recur yourself. Using Siddhartha … Read more
The first thing that makes me dubious about your code is that you are supposed to returning a series of strings, but your return value is a string. Perhaps, you should nail down your base case and recursive step. It looks like you’ve got a start on the base case. You can insert zero spaces … Read more
The observed behavior is affected by the HotSpot optimizer, however it is not the only cause. When I run the following code public static void main(String[] argv) { System.out.println(System.getProperty(“java.version”)); System.out.println(countDepth()); System.out.println(countDepth()); System.out.println(countDepth()); System.out.println(countDepth()); System.out.println(countDepth()); System.out.println(countDepth()); System.out.println(countDepth()); } static int countDepth() { try { return 1+countDepth(); } catch(StackOverflowError err) { return 0; } } with JIT … Read more
It is unspecified. Both compilers are right. Here are the relevant pieces from cppreference “initialization”. Static initialization For all other non-local static and thread-local variables, Zero initialization takes place So for all these variables, they are zero when the program loads. Then: Dynamic initialization After all static initialization is completed, dynamic initialization of non-local variables … Read more
If you relax the constraint that the Position column must contain integers from 1 to N and instead allow it to contain any numbers then you can do both searches and updates efficiently. You can insert an item between two other items with position A and B by calculating the average (A + B) DIV … Read more
The complexity is O(C(n,k)) which is O(n choose k). This ends up being equivalent to O(min(n^k, n^(n-k))).
I got a 20% performance boost by tightening up the code a bit but a whopping 400% increase by using a cache for split strings. That only makes a difference if you use the same spec multiple times. Here are sample implementations and a profile script to test. test.py mydict = { ‘first’: { ‘second’: … Read more