vaskoz’s gists

vaskoz / Palindromes.java

Created June 4, 2013 23:27

Print out the palindromes for a list of new line separated words read in from standard input. Usage: java Palindromes < /usr/share/dict/words

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

	public class Palindromes {
	public static void main(String[] args) {
	Set<String> words = new HashSet<String>();
	Scanner scanner = new Scanner(System.in);
	while (scanner.hasNext()) {
	String word = scanner.next().toLowerCase();

vaskoz / AlgorithmL.java

Created June 5, 2013 06:41

Implementation of Lexicographic Permutation Generation. Algorithm L by Knuth. Usage: java AlgorithmL "122233344555"

	import java.util.Arrays;

	public class AlgorithmL {
	public static void main(String[] args) {
	if (args.length != 1) {
	System.err.println("Usage: provide a string (quoted if multiword)");
	System.exit(1);
	}
	char[] letters = args[0].toCharArray();
	Arrays.sort(letters);

vaskoz / OpenCvExample.groovy

Created June 8, 2013 22:41

This Groovy code results in Exception in thread "main" java.lang.UnsatisfiedLinkError: org.opencv.core.Mat.n_eye(III)J

	import org.opencv.core.Core
	import org.opencv.core.CvType
	import org.opencv.core.Mat

	class Main {
	static { System.loadLibrary(Core.NATIVE_LIBRARY_NAME); }

	public static void main(String[] args) {
	Mat m = Mat.eye(3, 3, CvType.CV_8UC1);
	System.out.println("m = " + m.dump());

vaskoz / OpenCvExample.java

Created June 8, 2013 22:43

Java version of OpenCvExample. Works as expected.

	import org.opencv.core.Core;
	import org.opencv.core.CvType;
	import org.opencv.core.Mat;

	public class OtherMain {
	static { System.loadLibrary(Core.NATIVE_LIBRARY_NAME); }

	public static void main(String[] args) {
	Mat m = Mat.eye(3, 3, CvType.CV_8UC1);
	System.out.println("m = " + m.dump());

vaskoz / WorkingOpenCvExample.groovy

Created June 8, 2013 22:51

	import org.opencv.core.Core
	import org.opencv.core.CvType
	import org.opencv.core.Mat

	class Main {
	static {
	Runtime.getRuntime().loadLibrary0(groovy.lang.GroovyClassLoader.class, Core.NATIVE_LIBRARY_NAME)
	}

	public static void main(String[] args) {

vaskoz / OneSwapMinNumber.java

Last active December 19, 2015 11:19

Swap any num[i] and num[j] such that you return the smallest number possible.

	import java.util.Arrays;

	public class OneSwapMinNumber {
	/**
	* Worst case running time
	* O(11*k) - k is the number of digits in the number (length of string)
	*/
	public static String min(String num) {
	char[] digits = num.toCharArray();
	int[] rindex = new int[10];

vaskoz / InvokeStatic.java

Created July 9, 2013 04:58

Calling a static method is the one and only use case of invokestatic.

	public class InvokeStatic {
	public static void someStaticMethod() {}
	public static void main(String[] args) {
	someStaticMethod();
	}
	}

	//Compiled from "InvokeStatic.java"
	//public class InvokeStatic {
	// public InvokeStatic();

vaskoz / InvokeInterface.java

Last active December 19, 2015 12:28

Only gets used when calling a method on an object from an Interface type.

	public class InvokeInterface {
	public void methodA() {
	Runnable r = new Runnable() {
	@Override public void run() {}
	};
	r.run();
	}
	}

	//Compiled from "InvokeInterface.java"

vaskoz / InvokeSpecial.java

Created July 9, 2013 05:14

Invokespecial used in 3 cases: call to super method, call to constructor, and call to private methods.

	class A {
	public void superMethod() {}
	}

	public class InvokeSpecial extends A {
	// Implicit super constructor call - invokespecial
	private byte b = 0;
	{ // instance initializer - invokespecial
	b = 1;
	}

vaskoz / For.java

Created July 15, 2013 03:39

Nested for loops (N^2) where N is Integer.MAX_VALUE. javap -c Output of bytecode produced by javac compiler below that is the output produced by the PrintAssembly (hsdis) plugin.

	public class For {
	public static void main(String[] args) {
	char x = 'a';
	for (int i = 0; i < Integer.MAX_VALUE; i++)
	for (int j = 0; j < Integer.MAX_VALUE; j++)
	x = 'b';
	}
	}
	//***************************************************************************************
	// javap -c For

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