puzzle

Is there a case of ... or context where cat file | ... behaves differently than ... <file ? When reading from a regular file, cat is in charge of reading the data, performs it as it pleases, and might constrain it in the way it writes it to the pipeline. Obviously, the contents themselves are preserved, but anything else could be tainted. For example: block size and data arrival timing. Additionally, the pipe in itself isn't always neutral: it serves as an additional buffer between the input and ... . Quick and easy way to make the block size issue apparent: $ cat large-file | pv >/dev/null 5

I have a system that requires a unique 6-digit code to represent an object, and I'm trying to think of a good algorithm for generating them. Here are the pre-reqs: I'm using a base-20 system (no caps, numbers, vowels, or l to prevent confusion and naughty words) The base-20 allows 64 million combinations I'll be inserting potentially 5-10 thousand entries at once, so in theory I'd use bulk inserts, which means using a unique key probably won't be efficient or pretty (especially if there starts being lots of collisions) It's not out of the question to fill up 10% of the combinations so there's

In this earlier question the OP asked the following problem: Given a rectangular grid where some squares are empty and some are filled, what is the largest number of 2x1 dominoes that can be placed into the world such that no two dominos overlap and no domino is atop a filled square? The (quite beautiful!) answer to this problem recognized that this is equivalent to finding a maximum bipartite matching in a specially-constructed graph. In this graph, each empty square has a node that is linked to each of its neighbors by an edge. Each domino then corresponds to an edge in the graph such that

I have a question which asks us to reduce the string as follows. The input is a string having only A , B or C . Output must be length of the reduced string The string can be reduced by the following rules If any 2 different letters are adjacent, these two letters can be replaced by the third letter. Eg ABA -> CA -> B . So final answer is 1 (length of reduced string) Eg ABCCCCCCC This doesn't become CCCCCCCC , as it can be reduced alternatively by ABCCCCCCC -> AACCCCCC -> ABCCCCC -> AACCCC -> ABCCC -> AACC -> ABC -> AA as here length is 2 < (length of CCCCCCCC ) How do you go about this problem

The criminal is one of A, B, C and D. A says: "It's not me" B says: "It's D" C says: "It's B" D says: "It's not me" And we know that only one of them tells the truth. Who is the one? I want to solve it by using Prolog. It's an interview question. One-liner solution ?- member(K,[a,b,c,d]),(K\=a->A=1;A=0),(K=d->B=1;B=0),(K=b->C=1;C=0),(K\=d->D=1;D=0),A+B+C+D=:=1. K = a, A = 0, B = 0, C = 0, D = 1 ; false. Disclaimer : This is Xonix ' solution. If you like it vote him up. But as it took me some head-scratching to figure out what was going on, I thought I might just as well offer my comments so

Without running this code, identify which Foo method will be called: class A { public void Foo( int n ) { Console.WriteLine( "A::Foo" ); } } class B : A { /* note that A::Foo and B::Foo are not related at all */ public void Foo( double n ) { Console.WriteLine( "B::Foo" ); } } static void Main( string[] args ) { B b = new B(); /* which Foo is chosen? */ b.Foo( 5 ); } Which method? And why? No cheating by running the code. I found this puzzle on the web; I like it and I think I'm going to use it as an interview question...Opinions? EDIT: I wouldn't judge a candidate on getting this wrong, I'd