Like described by Jon Skeet in this SO answer, it is best practice to pick some prime numbers and multiply these with the single hash codes, then sum everything up. public int GetHashCode() { unchecked { int hash = 17; // Maybe nullity checks, if these are objects not primitives! hash = hash * 23 … Read more
A predicate (‘PRED-i-cat’) is the part of a sentence that contains the verb and tells you something about the subject. For instance, in the sentence “Mike is eating”, we have the subject, ‘Mike’, and the predicate, ‘is eating’. In the context of computer science, we aren’t interested in stating a fact, but rather, in testing … Read more
A fixed point number has a specific number of bits (or digits) reserved for the integer part (the part to the left of the decimal point) and a specific number of bits reserved for the fractional part (the part to the right of the decimal point). No matter how large or small your number is, … Read more
Yes, this is standard practice in academic literature. To understand it, it helps to know that the notion of “type” was invented in the 1930s, in the context of lambda calculus (in fact, even earlier, in the context of set theory). Since then, a whole branch of computational logic has emerged that is known as … Read more
Generally it means that by increasing the level of abstraction one can make the problem easier to understand/resolve. Be careful with your abstractions though, the full quote at least as I heard it is, “You can solve every problem with another level of indirection, except for the problem of too many levels of indirection”.
Watch this lecture. The idea is that your program is a combination of a datatype and operations over it. The problem asks for an implementation that allows to add new cases of the type and new operations without the need for recompilation of the old modules and keeping static type safety(no casts or runtime type … Read more
Theres a few ways you can do this. You can either add a background to the canvas you are currently working on, which if the canvas isn’t going to be redrawn every loop is fine. Otherwise you can make a second canvas underneath your main canvas and draw the background to it. The final way … Read more
Closures, lambdas, and anonymous functions are not necessarily the same thing. An anonymous function is any function that doesn’t have (or, at least, need) its own name. A closure is a function that can access variables that were in its lexical scope when it was declared, even after they have fallen out of scope. Anonymous … Read more
Tries, also known as prefix-trees or crit-bit trees, have existed for over 40 years but are still relatively unknown. A very cool use of tries is described in “TRASH – A dynamic LC-trie and hash data structure”, which combines a trie with a hash function.
Usually for this type of question, if the regex is not simple enough to be derived directly, you can start from drawing a DFA and derive a regex from there. You should be able to derive the following DFA. q1, q2, q3, q4 are end states, with q1 also being the start state. q5 is … Read more