You should use the fact that when you want all permutations of N numbers there are N! possibilities. Therefore each number x from 1..N! encodes such a permutation. Here is a sample that iteratively prints out all permutations of a sting. private static void printPermutationsIterative(String string){ int [] factorials = new int[string.length()+1]; factorials[0] = 1; … Read more
C# compiler does not give you any guarantees about tail-call optimizations because C# programs usually use loops and so they do not rely on the tail-call optimizations. So, in C#, this is simply a JIT optimization that may or may not happen (and you cannot rely on it). F# compiler is designed to handle functional … Read more
When you define a semantics of function definition, as a language designer, you have choices: either to make the name of the function visible in the scope of its own body, or not. Both choices are perfectly legal, for example C-family languages being far from functional, still do have names of definitions visible in their … Read more
I’m wondering whether you meant “recursive”. Here is a simple example of a recursive function to compute the factorial function: def factorial(n): if n == 0: return 1 else: return n * factorial(n – 1) The two key elements of a recursive algorithm are: The termination condition: n == 0 The reduction step where the … Read more
This one should do it: get-childitem -Include .svn -Recurse -force | Remove-Item -Force -Recurse Other version: $fso = New-Object -com “Scripting.FileSystemObject” $folder = $fso.GetFolder(“C:\Test\”) foreach ($subfolder in $folder.SubFolders) { If ($subfolder.Name -like “*.svn”) { remove-item $subfolder.Path -Verbose } }
function allDescendants (node) { for (var i = 0; i < node.childNodes.length; i++) { var child = node.childNodes[i]; allDescendants(child); doSomethingToNode(child); } } You loop over all the children, and for each element, you call the same function and have it loop over the children of that element.
You are looking for the set intersection of all the sublists, and the data type you should use for set operations is a set: result = set(p[0]) for s in p[1:]: result.intersection_update(s) print result
That code is most likely equal to this: TimePoint now_ = TimePoint::min(); That means, min() is a static method, and calling it using an instance is same as calling it like this, the instance is used just for determining the type. No black magic involved, that’s just two syntaxes for doing the same thing. As … Read more
In this way the code looks a bit simpler import static java.nio.file.StandardCopyOption.*; public void copyFolder(Path src, Path dest) throws IOException { try (Stream<Path> stream = Files.walk(src)) { stream.forEach(source -> copy(source, dest.resolve(src.relativize(source)))); } } private void copy(Path source, Path dest) { try { Files.copy(source, dest, REPLACE_EXISTING); } catch (Exception e) { throw new RuntimeException(e.getMessage(), e); } … Read more
Here’s an alternative implementation of the comparison function with filecmp module. It uses a recursion instead of os.walk, so it is a little simpler. However, it does not recurse simply by using common_dirs and subdirs attributes since in that case we would be implicitly using the default “shallow” implementation of files comparison, which is probably … Read more