joriki’s gists

joriki / Question260072.java

Created December 16, 2012 21:27

Find cycles of three six-sided dice such that each beats the next one with the same maximal probability; see http://math.stackexchange.com/questions/260072.

	public class Question260072 {
	public static void main (String [] args) {
	int [] [] dice = new int [3] [6];
	int [] counter = new int [3];

	int limit = (int) Math.pow (3,18);
	int max = 0;

	outer:
	for (int selection = 0;selection < limit;selection++) {

joriki / Question261357.java

Created December 19, 2012 00:48

Calculate probabilities of breaking even or winning at least the expected value at some point in a series of bets; see http://math.stackexchange.com/questions/261357.

	public class Question261357 {
	final static boolean even = false;
	final static int percent = 74;
	final static double p = percent / 100.;
	final static int win = 7;
	final static int lose = 6;

	static double [] [] cache;
	static boolean [] [] done;

joriki / Question262629.java

Created December 20, 2012 13:59

Calculate the number of possible draws in the draw for the round of 16 in the 2012–13 UEFA Champions League; see http://math.stackexchange.com/questions/262629.

	public class Question262629 {
	final static String [] [] associations =
	{
	{"FRA","GER","SPA","GER","ITA","GER","SPA","ENG"},
	{"POR","ENG","ITA","SPA","UKR","SPA","SCO","TUR"}
	};

	static int count;
	static boolean [] paired = new boolean [8];

joriki / Question264698.java

Created December 25, 2012 13:29

Calculate the average number of edges in a graph uniformly randomly selected from all acyclic digraphs on n nodes with at most one incoming edge and at most one outgoing edge at each node; see http://math.stackexchange.com/questions/264698.

	import java.math.BigInteger;

	public class Question264698 {
	final static int max = 10000;

	final static BigInteger quotientFactor = BigInteger.valueOf ((1L << 63) - 1);
	public static double quotient (BigInteger num,BigInteger den) {
	return num.multiply (quotientFactor).divide (den).doubleValue () / quotientFactor.doubleValue ();
	}

joriki / Question273348.java

Last active December 10, 2015 20:58

Count the number of distinct circles through at least three grid points in a square grid; see http://math.stackexchange.com/questions/273348.

	import java.util.HashSet;
	import java.util.Set;

	public class Question273348 {
	public static long gcd (long p,long q) {
	if (p < 0)
	p = -p;
	if (q < 0)
	q = -q;

joriki / Question279924.java

Created January 16, 2013 11:00

Estimate the expected number of uniformly randomly selected derangements of non-fixed points required to sort a uniformly randomly selected permutation of n items; see http://math.stackexchange.com/questions/279924.

	import java.util.Arrays;
	import java.util.Locale;
	import java.util.Random;

	public class Question279924 {
	final static int ntrials = 100000;

	static Random random = new Random (0);

	static void makeRandomPermutation (int [] p,int n) {

joriki / Question280648.java

Created January 17, 2013 22:49

Estimate the probability that some subset of k out of n points uniformly randomly selected in the unit square forms a convex polygon; see http://math.stackexchange.com/questions/280648.

	import java.util.Random;

	public class Question280648 {
	final static int ntrials = 1000000;
	final static Random random = new Random ();

	static class CombinationTraversal {
	int k,n;
	int [] combination;

joriki / Question281094.java

Last active December 11, 2015 06:48

Search for permutations of objects in a circle for which any pair of objects is at a different minimal distance along the circle than originally; see http://math.stackexchange.com/questions/281094.

	public class Question281094 {
	static int m;
	static int [] p;
	static int count;

	public static void main (String [] args) {
	for (m = 2;;m++) {
	p = new int [m];
	p [0] = 1;
	count = 0;

joriki / Question280793.java

Created January 19, 2013 07:46

Estimate the expected value and variance of a transitivity ratio in a random graph; see http://math.stackexchange.com/questions/280793.

	import java.util.Random;

	public class Question280793 {
	final static int n = 100;
	final static int M = 150;

	final static int N = (n * (n - 1)) / 2;

	final static Random random = new Random ();

joriki / Question281993.java

Created January 19, 2013 14:08

Estimate the probability of two points uniformly randomly chosen in a square or circle to lie on the same side of the line joining two other points thus chosen; see http://math.stackexchange.com/questions/281993.

	public class Question281993 {
	final static boolean square = false;
	final static int ntrials = 10000000;

	public static void main (String [] args) {
	int count = 0;
	double [] [] x = new double [4] [2];
	for (int n = 0;n < ntrials;n++) {
	for (int i = 0;i < 4;i++)
	for (;;) {

Felix Pahl joriki