The time complexity, in Big O notation, for each function: int recursiveFun1(int n) { if (n <= 0) return 1; else return 1 + recursiveFun1(n-1); } This function is being called recursively n times before reaching the base case so its O(n), often called linear. int recursiveFun2(int n) { if (n <= 0) return 1; … Read more
This should give the location of the files that contain your pattern: Get-ChildItem -Recurse | Select-String “dummy” -List | Select Path
Usually, I replace a recursive algorithm by an iterative algorithm by pushing the parameters that would normally be passed to the recursive function onto a stack. In fact, you are replacing the program stack by one of your own. var stack = []; stack.push(firstObject); // while not empty while (stack.length) { // Pop off end … Read more
Try this one: #!/bin/bash find $1 -type f -exec stat –format ‘%Y :%y %n’ “{}” \; | sort -nr | cut -d: -f2- | head Execute it with the path to the directory where it should start scanning recursively (it supports filenames with spaces). If there are lots of files it may take a while … Read more
find “$directory” -type f -name “*.in” is a bit shorter than that whole thing (and safer – deals with whitespace in filenames and directory names). Your script is probably failing for entries that don’t have a . in their name, making $extension empty.
Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax. WITH RECURSIVE MyTree AS ( SELECT * FROM MyTable WHERE ParentId IS NULL UNION ALL SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentId = t.Id ) SELECT * FROM MyTree; … Read more
It is a guard against a stack overflow, yes. Python (or rather, the CPython implementation) doesn’t optimize tail recursion, and unbridled recursion causes stack overflows. You can check the recursion limit with sys.getrecursionlimit: import sys print(sys.getrecursionlimit()) and change the recursion limit with sys.setrecursionlimit: sys.setrecursionlimit(1500) but doing so is dangerous — the standard limit is a … Read more
Tail-call optimization is where you are able to avoid allocating a new stack frame for a function because the calling function will simply return the value that it gets from the called function. The most common use is tail-recursion, where a recursive function written to take advantage of tail-call optimization can use constant stack space. … Read more
Consider a simple function that adds the first N natural numbers. (e.g. sum(5) = 0 + 1 + 2 + 3 + 4 + 5 = 15). Here is a simple JavaScript implementation that uses recursion: function recsum(x) { if (x === 0) { return 0; } else { return x + recsum(x – 1); … Read more