puzzle

I was given a puzzle as a present. It consists of 4 cubes, arranged side by side. The faces of each cube are one of four colours. To solve the puzzle, the cubes must be orientated so that all four cubes' tops are different, all their fronts are different, all their backs are different and all their bottom's are different. The left and right sides do not matter. My pseudo-code solution was: Create a representation of each cube. Get all the possible orientations of each cube (there are 24 for each). Get all the possible combinations of orientations of each cube. Find the combination of

why is 24 * 60 * 60 * 1000 * 1000 divided by 24 * 60 * 60 * 1000 not equal to 1000 in Java? Because the multiplication overflows 32 bit integers. In 64 bits it's okay: public class Test { public static void main(String[] args) { int intProduct = 24 * 60 * 60 * 1000 * 1000; long longProduct = 24L * 60 * 60 * 1000 * 1000; System.out.println(intProduct); // Prints 500654080 System.out.println(longProduct); // Prints 86400000000 } } Obviously after the multiplication has overflowed, the division isn't going to "undo" that overflow. You need to start with 24L * 60 * ... because the int overflows.

I've a panel of size X by Y. I want to place up to N rectangles, sized randomly, upon this panel, but I don't want any of them to overlap. I need to know the X, Y positions for these rectangles. Algorithm, anyone? Edit : All the N rectangles are known at the outset and can be selected in any order. Does that change the procedure? You can model this by a set of "free" rectangles, starting with single one with coordinates of 0,0, size (x, y). Each time you need to add one more rectangle, choose one of remaining "free" rectangles, generate new rectangle (with top-left coordinate and size such

My friend says it's possible to write a C program that will print "hello world" without IF/WHILE/FOR and without semicolons. After minimal research I told her it was not possible. Is it possible? I've been trying to find a "portable" way of stealing a semicolon from an include file. This works under Linux: int main(int ac, char **av) { #define typedef #define uint8_t a[printf("hello world\n")] #include <stdint.h> } This causes the one typedef unsigned char uint8_t to become my printf. Another trick that worked was to #define away every standard stdint type such that stdint.h reduces to a bunch

I'm trying to come up with some programming puzzles focused on multi-threading. Most of the problems I've been able to come up with, so far, have been pretty domain specific. Does anybody have any decent programming puzzles for developers attempting to learn the core concepts of multi-threading applications? There are a number of topics covered at this link. Multithreaded Programming with ThreadMentor : A Tutorial Edit: Here are some direct links to the problems listed at that link, along with their initial descriptions. ThreadMentor : The Dining Philosopher's Problem ThreadMentor : The Dining