I’m trying to find the definition of a binary search tree and I keep finding different definitions everywhere. Some say that for any given subtree the left child key is less than or equal to the root. Some say that for any given subtree the right child key is greater than or equal to the … Read more
A frozen set is a frozenset. A frozen list could be a tuple. What would a frozen dict be? An immutable, hashable dict. I guess it could be something like collections.namedtuple, but that is more like a frozen-keys dict (a half-frozen dict). Isn’t it? A “frozendict” should be a frozen dictionary, it should have keys, … Read more
I am using std::queue for implementing JobQueue class. ( Basically this class process each job in FIFO manner). In one scenario, I want to clear the queue in one shot( delete all jobs from the queue). I don’t see any clear method available in std::queue class. How do I efficiently implement the clear method for … Read more
I’ve been learning about different algorithms in my spare time recently, and one that I came across which appears to be very interesting is called the HyperLogLog algorithm – which estimates how many unique items are in a list. This was particularly interesting to me because it brought me back to my MySQL days when … Read more
How can I print a binary tree in Java so that the output is like: 4 / \ 2 5 My node: public class Node<A extends Comparable> { Node<A> left, right; A data; public Node(A data){ this.data = data; } } 21 Answers 21
In C, I know I can dynamically allocate a two-dimensional array on the heap using the following code: int** someNumbers = malloc(arrayRows*sizeof(int*)); for (i = 0; i < arrayRows; i++) { someNumbers[i] = malloc(arrayColumns*sizeof(int)); } Clearly, this actually creates a one-dimensional array of pointers to a bunch of separate one-dimensional arrays of integers, and “The … Read more
I have a Hashmap in Java like this: private Map<String, Integer> team1 = new HashMap<String, Integer>(); Then I fill it like this: team1.put(“United”, 5); How can I get the keys? Something like: team1.getKey() to return “United”. 15 Answers 15
I’ve seen people say that set objects in python have O(1) membership-checking. How are they implemented internally to allow this? What sort of data structure does it use? What other implications does that implementation have? Every answer here was really enlightening, but I can only accept one, so I’ll go with the closest answer to … Read more
Why would someone want to use a linked-list over an array? Coding a linked-list is, no doubt, a bit more work than using an array and one may wonder what would justify the additional effort. I think insertion of new elements is trivial in a linked-list but it’s a major chore in an array. Are … Read more
As I was programming, I haven’t seen an instance where an array is better for storing information than another form thereof. I had indeed figured the added “features” in programming languages had improved upon this and by that replaced them. I see now that they aren’t replaced but rather given new life, so to speak. … Read more
