Generación de números primos.

Código (Limit.java):

package limit;

public class Limit {

    public static void main(String[] args) {
        boolean p;
        int limit = 100;
        String aux = "";
        for (int n = 3; n < limit; n++) {
            p = esPrimo(n);
            aux += p ? n : "·";
        }
        System.out.println(aux);        
    }

    private static boolean esPrimo(int n) {
        //es numero par?
        if (n % 2 == 0) {
            return false;
        }
        //es numero multiplo del resto de numeros impares?
        for (int i = 3; i * i <= n; i += 2) {
            if (n % i == 0) {
                return false;
            }
        }
        return true;
    }

}


Resultado:

run:
3·5·7···11·13···17·19···23·····29·31·····37···41·43···47·····53·····59·61·····67···71·73·····79···83·····89·······97··
BUILD SUCCESSFUL (total time: 0 seconds)

Generación de laberintos IV. Formato final 1024x768.

Código 1 (Blogspot_Laberinto_final.java):

package blogspot_laberinto_final;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Blogspot_Laberinto_final {

    public static void main(String[] args) {

        //tamaño laberinto (núm. bloques)
        int x = 21;
        int y = 29;

        //generar laberinto aleatorio
        String strMaze = new LineMaze(new BinMaze(new Maze(y - 2, x - 2).toString(), x, y).toMatrix(), x, y).toString();

        //tamaño lienzo
        int res_x = 1024;
        int res_y = 768;

        BufferedImage imagen = new BufferedImage(res_x, res_y, BufferedImage.TYPE_INT_RGB);
        Lienzo.Dibujar((Graphics2D) imagen.getGraphics(), res_x, res_y, strMaze);
        try {
            ImageIO.write(imagen, "png", new File("Laberinto.png"));
        } catch (IOException e) {
        }

    }

}


Código 2 (Maze.java):

package blogspot_laberinto;

import java.util.LinkedList;
import java.util.Random;

public class Maze {

    public static final char PASSAGE_CHAR = ' ';
    public static final char WALL_CHAR = '█';
    public static final boolean WALL = false;
    public static final boolean PASSAGE = !WALL;

    private final boolean map[][];
    private final int width;
    private final int height;

    public Maze(final int width, final int height) {
        this.width = width;
        this.height = height;
        this.map = new boolean[width][height];

        final LinkedList<int[]> frontiers = new LinkedList<>();
        final Random random = new Random();
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        frontiers.add(new int[]{x, y, x, y});

        while (!frontiers.isEmpty()) {
            final int[] f = frontiers.remove(random.nextInt(frontiers.size()));
            x = f[2];
            y = f[3];
            if (map[x][y] == WALL) {
                map[f[0]][f[1]] = map[x][y] = PASSAGE;
                if (x >= 2 && map[x - 2][y] == WALL) {
                    frontiers.add(new int[]{x - 1, y, x - 2, y});
                }
                if (y >= 2 && map[x][y - 2] == WALL) {
                    frontiers.add(new int[]{x, y - 1, x, y - 2});
                }
                if (x < width - 2 && map[x + 2][y] == WALL) {
                    frontiers.add(new int[]{x + 1, y, x + 2, y});
                }
                if (y < height - 2 && map[x][y + 2] == WALL) {
                    frontiers.add(new int[]{x, y + 1, x, y + 2});
                }
            }
        }

    }

    @Override
    public String toString() {
        final StringBuffer b = new StringBuffer();
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        for (int y = 0; y < height; y++) {
            b.append(WALL_CHAR);
            for (int x = 0; x < width; x++) {
                b.append(map[x][y] == WALL ? WALL_CHAR : PASSAGE_CHAR);
            }
            b.append(WALL_CHAR);
            b.append('\n');
        }
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        return b.toString();
    }

}


Código 3 (BinMaze.java):

package blogspot_laberinto_final;

public class BinMaze {

    char[] vMaze;
    boolean[][] mMaze;

    public BinMaze(String strMaze, int x, int y) {
        vMaze = strMaze.replace("\n", "").toCharArray();
        mMaze = new boolean[x + 2][y + 2]; //se suma 2 para los bordes (ahorrar codigo)
        int cont = 0;
        for (int i = 1; i < x + 1; i++) {
            for (int j = 1; j < y + 1; j++) {
                mMaze[i][j] = vMaze[cont] == '█';
                cont++;
            }
        }
    }

    public boolean[][] toMatrix() {
        return mMaze;
    }

    public char[] toArray() {
        return vMaze;
    }

}


Código 4 (LineMaze.java):

package blogspot_laberinto_final;

public class LineMaze {

    String styleMap;

    public LineMaze(boolean[][] mMaze, int x, int y) {

        this.styleMap = "";
        String strMuro = " ├┬┌┤─┐┬┴└│├┘┴┤┼";
        boolean[][] mCod = combina();
        for (int i = 1; i < x + 1; i++) {
            for (int j = 1; j < y + 1; j++) {
                if (mMaze[i][j]) { // si hay muro
                    for (int k = 0; k < 16; k++) {
                        if (mMaze[i - 1][j] == mCod[k][0] && mMaze[i][j - 1] == mCod[k][1] && mMaze[i + 1][j] == mCod[k][2] && mMaze[i][j + 1] == mCod[k][3]) {
                            styleMap += strMuro.charAt(k);
                        }
                    }
                } else {
                    styleMap += " ";
                }
            }
            styleMap += "\n";
        }

    }    
    
    @Override
    public String toString() {        
        return styleMap;
    }

    private boolean[][] combina() {
        String cod;
        boolean[][] mCod = new boolean[16][4];
        for (int i = 0; i < 16; i++) {
            cod = Integer.toBinaryString(i);
            while (cod.length() < 4) {
                cod = "0" + cod;
            }
            for (int j = 0; j < cod.length(); j++) {
                mCod[i][j] = cod.charAt(j) == '1';
            }
        }
        return mCod;
    }

}


Código 5 (Lienzo.java):

package blogspot_laberinto_final;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Stroke;

class Lienzo {

    static void Dibujar(Graphics2D g, int x, int y, String strMaze) {

        //tamaño bloque 32x32
        int bloque_x = 32;
        int bloque_y = 32;

        String[] arrMaze = strMaze.split("\n");

        //grosor muro
        Stroke stroke5 = new BasicStroke(15f);

        //fondo blanco
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, x, y);

        //color muro
        g.setColor(Color.BLUE);
        int x0, y0;
        for (int j = 0; j < arrMaze.length; j++) {
            for (int i = 0; i < arrMaze[0].length(); i++) {
                if (arrMaze[j].charAt(i) != ' ') {
                    x0 = ((i + 1) * bloque_x) + bloque_x / 2;
                    y0 = ((j + 1) * bloque_y) + bloque_y / 2;
                    g.setStroke(stroke5);

                    switch (arrMaze[j].charAt(i)) {
                        case '─':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            break;
                        case '│':
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + bloque_y);
                            break;
                        case '┼':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + bloque_y);
                            break;
                        case '┬':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + bloque_y);
                            break;
                        case '┴':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 - bloque_y);
                            break;
                        case '├':
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + bloque_y);
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            break;
                        case '┤':
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + bloque_y);
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + (bloque_y / 2));
                            break;
                        case '┌':
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + bloque_y);
                            break;
                        case '┐':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + bloque_y);
                            break;
                        case '└':
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0 + (bloque_y / 2), x0 + bloque_x, y0 + (bloque_y / 2));
                            break;
                        case '┘':
                            g.drawLine(x0, y0 + (bloque_y / 2), x0 + (bloque_x / 2), y0 + (bloque_y / 2));
                            g.drawLine(x0 + (bloque_x / 2), y0, x0 + (bloque_x / 2), y0 + (bloque_y / 2));
                            break;
                        default:
                            break;
                    }

                }
            }
        }
    }

}


Resultado:

Generación de laberintos III. Guardar en formato .png (mini)

Generación de laberintos aleatorios con formato .png. Comprimido al máximo posible. Un pixel equivale a un bloque de muro (█).


Código 1 (Blogspot_Laberinto_png):

package blogspot_laberinto_png;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Blogspot_Laberinto_png {

    public static void main(String[] args) {

        // tamaño laberinto
        int x = 97;
        int y = 97;

        String strMaze = new Maze(y - 2, x - 2).toString();

        // resolucion de imagen .png
        int res_x = 99;
        int res_y = 99;

        BufferedImage imagen = new BufferedImage(res_x, res_y, BufferedImage.TYPE_INT_RGB);
        Lienzo.Dibujar((Graphics2D) imagen.getGraphics(), res_x, res_y, strMaze);
        try {
            ImageIO.write(imagen, "png", new File("Laberinto.png"));
        } catch (IOException e) {
        }

    }
}


Código 2 (Lienzo.java):

package blogspot_laberinto;

import java.awt.Color;
import java.awt.Graphics2D;

class Lienzo {

    static void Dibujar(Graphics2D g, int x, int y, String strMaze) {
        
        //tamaño bloque (1x1 pixels)
        int tCuadroX = 1;

        String[] arrMaze = strMaze.split("\n");

        //fondo blanco
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, x, y);

        //dibujar bloques muro
        g.setColor(Color.BLUE);
        for (int j = 0; j < arrMaze.length; j++) {
            for (int i = 0; i < arrMaze.length; i++) {
                if (arrMaze[j].charAt(i) != ' ') {
                    g.fillRect(tCuadroX * (i + 1), tCuadroX * (j + 1), tCuadroX, tCuadroX);
                }
            }
        }
    }

}


Código 3 (Maze.java):

package blogspot_laberinto_png;

import java.util.LinkedList;
import java.util.Random;

public class Maze {

    public static final char PASSAGE_CHAR = ' ';
    public static final char WALL_CHAR = '█';
    public static final boolean WALL = false;
    public static final boolean PASSAGE = !WALL;

    private final boolean map[][];
    private final int width;
    private final int height;

    public Maze(final int width, final int height) {
        this.width = width;
        this.height = height;
        this.map = new boolean[width][height];

        final LinkedList<int[]> frontiers = new LinkedList<>();
        final Random random = new Random();
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        frontiers.add(new int[]{x, y, x, y});

        while (!frontiers.isEmpty()) {
            final int[] f = frontiers.remove(random.nextInt(frontiers.size()));
            x = f[2];
            y = f[3];
            if (map[x][y] == WALL) {
                map[f[0]][f[1]] = map[x][y] = PASSAGE;
                if (x >= 2 && map[x - 2][y] == WALL) {
                    frontiers.add(new int[]{x - 1, y, x - 2, y});
                }
                if (y >= 2 && map[x][y - 2] == WALL) {
                    frontiers.add(new int[]{x, y - 1, x, y - 2});
                }
                if (x < width - 2 && map[x + 2][y] == WALL) {
                    frontiers.add(new int[]{x + 1, y, x + 2, y});
                }
                if (y < height - 2 && map[x][y + 2] == WALL) {
                    frontiers.add(new int[]{x, y + 1, x, y + 2});
                }
            }
        }

    }

    @Override
    public String toString() {
        final StringBuffer b = new StringBuffer();
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        for (int y = 0; y < height; y++) {
            b.append(WALL_CHAR);
            for (int x = 0; x < width; x++) {
                b.append(map[x][y] == WALL ? WALL_CHAR : PASSAGE_CHAR);
            }
            b.append(WALL_CHAR);
            b.append('\n');
        }
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        return b.toString();
    }

}


Resultado:

Conversión decimal > binario > boleano

Código (Conversiones.java):

package conversiones;

import java.util.Arrays;

public class Conversiones {
    public static void main(String[] args) {
        System.out.println("Dec\tBin\tBoolean");
        String cod;
        boolean[] mCod;
        for (int i = 0; i < 16; i++) {
            cod = Integer.toBinaryString(i);
            while (cod.length() < 4) {
                cod = "0" + cod;
            }
            mCod = new boolean[cod.length()];
            for (int j = 0; j < cod.length(); j++) {
                mCod[j] = cod.charAt(j) == '1';
            }
            System.out.println(i + "\t" + cod + "\t" + Arrays.toString(mCod));
        }
    }
}


Resultado:

run:
Dec  Bin     Boolean
0    0000    [false, false, false, false]
1    0001    [false, false, false, true]
2    0010    [false, false, true, false]
3    0011    [false, false, true, true]
4    0100    [false, true, false, false]
5    0101    [false, true, false, true]
6    0110    [false, true, true, false]
7    0111    [false, true, true, true]
8    1000    [true, false, false, false]
9    1001    [true, false, false, true]
10   1010    [true, false, true, false]
11   1011    [true, false, true, true]
12   1100    [true, true, false, false]
13   1101    [true, true, false, true]
14   1110    [true, true, true, false]
15   1111    [true, true, true, true]
BUILD SUCCESSFUL (total time: 0 seconds)

Generación de laberintos II. Cambio de formato.

Ejemplo de tranformación: 

Código 1 (Blogspot_Laberinto.java):

package blogspot_laberinto;

public class Blogspot_Laberinto {

    public static void main(String[] args) {

        // Tamaño laberinto
        int x = 15;
        int y = 27;

        String strMaze = new Maze(y - 2, x - 2).toString();
        boolean[][] map0 = new StructMaze(strMaze, x, y).mMaze;
        StyleMaze sm = new StyleMaze(map0, x, y);

        // mostrar resultados
        System.out.println("\nLaberinto formato 1:\n");
        System.out.println(strMaze);
        System.out.println("\nLaberinto formato 2:\n");
        System.out.println(sm.map1);

    }

    private static class StructMaze {

        char[] vMaze;
        boolean[][] mMaze;

        public StructMaze(String strMaze, int x, int y) {
            vMaze = strMaze.replace("\n", "").toCharArray();
            mMaze = new boolean[x + 2][y + 2]; //se suma 2 para los bordes (ahorrar codigo)
            int cont = 0;
            for (int i = 1; i < x + 1; i++) {
                for (int j = 1; j < y + 1; j++) {
                    mMaze[i][j] = vMaze[cont] == '█';
                    cont++;
                }
            }
        }
    }

}


Código 2 (Maze.java):

package blogspot_laberinto;

import java.util.LinkedList;
import java.util.Random;

public class Maze {

    public static final char PASSAGE_CHAR = ' ';
    public static final char WALL_CHAR = '█';
    public static final boolean WALL = false;
    public static final boolean PASSAGE = !WALL;

    private final boolean map[][];
    private final int width;
    private final int height;

    public Maze(final int width, final int height) {
        this.width = width;
        this.height = height;
        this.map = new boolean[width][height];

        final LinkedList<int[]> frontiers = new LinkedList<>();
        final Random random = new Random();
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        frontiers.add(new int[]{x, y, x, y});

        while (!frontiers.isEmpty()) {
            final int[] f = frontiers.remove(random.nextInt(frontiers.size()));
            x = f[2];
            y = f[3];
            if (map[x][y] == WALL) {
                map[f[0]][f[1]] = map[x][y] = PASSAGE;
                if (x >= 2 && map[x - 2][y] == WALL) {
                    frontiers.add(new int[]{x - 1, y, x - 2, y});
                }
                if (y >= 2 && map[x][y - 2] == WALL) {
                    frontiers.add(new int[]{x, y - 1, x, y - 2});
                }
                if (x < width - 2 && map[x + 2][y] == WALL) {
                    frontiers.add(new int[]{x + 1, y, x + 2, y});
                }
                if (y < height - 2 && map[x][y + 2] == WALL) {
                    frontiers.add(new int[]{x, y + 1, x, y + 2});
                }
            }
        }

    }

    @Override
    public String toString() {
        final StringBuffer b = new StringBuffer();
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        for (int y = 0; y < height; y++) {
            b.append(WALL_CHAR);
            for (int x = 0; x < width; x++) {
                b.append(map[x][y] == WALL ? WALL_CHAR : PASSAGE_CHAR);
            }
            b.append(WALL_CHAR);
            b.append('\n');
        }
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        return b.toString();
    }

}


Código 3 (StyleMaze.java):

package blogspot_laberinto;

public class StyleMaze {

    public String map1;

    public StyleMaze(boolean[][] p0, int x, int y) {
        this.map1 = "";
        String strMuro = " ├┬┌┤─┐┬┴└│├┘┴┤┼";
        boolean[][] mCod = combina();
        for (int i = 1; i < x + 1; i++) {
            for (int j = 1; j < y + 1; j++) {
                if (p0[i][j]) { // si hay muro
                    for (int k = 0; k < 16; k++) {
                        if (p0[i - 1][j] == mCod[k][0] && p0[i][j - 1] == mCod[k][1] && p0[i + 1][j] == mCod[k][2] && p0[i][j + 1] == mCod[k][3]) {
                            map1 += strMuro.charAt(k);
                        }
                    }
                } else {
                    map1 += " ";
                }
            }
            map1 += "\n";
        }
    }

    private boolean[][] combina() {
        String cod;
        boolean[][] mCod = new boolean[16][4];
        for (int i = 0; i < 16; i++) {
            cod = Integer.toBinaryString(i);
            while (cod.length() < 4) {
                cod = "0" + cod;
            }
            for (int j = 0; j < cod.length(); j++) {
                mCod[i][j] = cod.charAt(j) == '1';
            }
        }
        return mCod;
    }

}


Resultado:

run:

Laberinto formato 1:

███████████████████████████
█ █       █ █ █         █ █
█ █████ ███ █ █ █ █ █████ █
█       █   █   █ █       █
███████ ███ █ ███ █ █ █████
█       █   █ █ █ █ █ █ █ █
███ ███ ███ ███ █ █████ █ █
█   █     █ █ █   █ █ █   █
█████████ █ █ ███ █ █ █ ███
█               █     █ █ █
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Laberinto formato 2:

┌─┬───────┬─┬─┬─────────┬─┐
│ │       │ │ │         │ │
│ └───┤ ┌─┘ │ ┴ ┬ ┬ ├───┘ │
│       │   │   │ │       │
├─────┤ ├─┤ │ ┌─┤ │ ┬ ┌─┬─┤
│       │   │ │ │ │ │ │ │ │
├─┤ ┌─┤ └─┐ ├─┤ ┴ ├─┼─┤ ┴ │
│   │     │ │ │   │ │ │   │
├───┴───┤ ┴ ┴ └─┐ ┴ ┴ │ ┌─┤
│               │     │ │ │
├───┬─┤ ┌─┤ ┌─┤ ┴ ├───┘ ┴ │
│   │   │   │             │
├─┤ └───┘ ┬ │ ┬ ├───┐ ┬ ├─┤
│         │ │ │     │ │   │
└─────────┴─┴─┴─────┴─┴───┘

BUILD SUCCESSFUL (total time: 0 seconds)

Generación de laberintos I.1. Algoritmo de Prim's 2.

Código 1 (Prime2.java):

package prime2;

public class Prime2 {

    public static void main(String[] args) {

        String laberinto = new Maze(31, 13).toString();
        System.out.println(laberinto);

    }

}


Código 2 (Maze.java):

package prime2;

import java.util.LinkedList;
import java.util.Random;

public class Maze {

    public static final char PASSAGE_CHAR = ' ';
    public static final char WALL_CHAR = '▓';
    public static final boolean WALL = false;
    public static final boolean PASSAGE = !WALL;

    private final boolean map[][];
    private final int width;
    private final int height;

    public Maze(final int width, final int height) {
        this.width = width;
        this.height = height;
        this.map = new boolean[width][height];

        final LinkedList<int[]> frontiers = new LinkedList<>();
        final Random random = new Random();
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        frontiers.add(new int[]{x, y, x, y});

        while (!frontiers.isEmpty()) {
            final int[] f = frontiers.remove(random.nextInt(frontiers.size()));
            x = f[2];
            y = f[3];
            if (map[x][y] == WALL) {
                map[f[0]][f[1]] = map[x][y] = PASSAGE;
                if (x >= 2 && map[x - 2][y] == WALL) {
                    frontiers.add(new int[]{x - 1, y, x - 2, y});
                }
                if (y >= 2 && map[x][y - 2] == WALL) {
                    frontiers.add(new int[]{x, y - 1, x, y - 2});
                }
                if (x < width - 2 && map[x + 2][y] == WALL) {
                    frontiers.add(new int[]{x + 1, y, x + 2, y});
                }
                if (y < height - 2 && map[x][y + 2] == WALL) {
                    frontiers.add(new int[]{x, y + 1, x, y + 2});
                }
            }
        }
    }

    @Override
    public String toString() {
        final StringBuffer b = new StringBuffer();
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        for (int y = 0; y < height; y++) {
            b.append(WALL_CHAR);
            for (int x = 0; x < width; x++) {
                b.append(map[x][y] == WALL ? WALL_CHAR : PASSAGE_CHAR);
            }
            b.append(WALL_CHAR);
            b.append('\n');
        }
        for (int x = 0; x < width + 2; x++) {
            b.append(WALL_CHAR);
        }
        b.append('\n');
        return b.toString();
    }
}


Resultado:

Generación de laberintos I. Algoritmo de Prim's 1.

Autor algoritmo: J. Zong en "Maze Generation with Prim's Algorithm"

 

Código (Prim.java):

package prim;

import java.util.ArrayList;

public class Prim {

    public static void main(String[] args) {  // dimensions of generated maze
        int r = 13, c = 31;

        // build maze and initialize with only walls
        StringBuilder s = new StringBuilder(c);
        for (int x = 0; x < c; x++) {
            s.append('█');
        }
        char[][] maz = new char[r][c];
        for (int x = 0; x < r; x++) {
            maz[x] = s.toString().toCharArray();
        }

        // select random point and open as start node
        Point st = new Point((int) (Math.random() * r), (int) (Math.random() * c), null);
        maz[st.r][st.c] = 'S';

        // iterate through direct neighbors of node
        ArrayList< Point> frontier = new ArrayList< Point>();
        for (int x = -1; x <= 1; x++) {
            for (int y = -1; y <= 1; y++) {
                if (x == 0 && y == 0 || x != 0 && y != 0) {
                    continue;
                }
                try {
                    if (maz[st.r + x][st.c + y] == ' ') {
                        continue;
                    }
                } catch (Exception e) { // ignore ArrayIndexOutOfBounds
                    continue;
                }
                // add eligible points to frontier
                frontier.add(new Point(st.r + x, st.c + y, st));
            }
        }

        Point last = null;
        while (!frontier.isEmpty()) {

            // pick current node at random
            Point cu = frontier.remove((int) (Math.random() * frontier.size()));
            Point op = cu.opposite();
            try {
                // if both node and its opposite are walls
                if (maz[cu.r][cu.c] == '█' && maz[op.r][op.c] == '█') {

                    // open path between the nodes
                    maz[cu.r][cu.c] = ' ';
                    maz[op.r][op.c] = ' ';

                    // store last node in order to mark it later
                    last = op;

                    // iterate through direct neighbors of node, same as earlier
                    for (int x = -1; x <= 1; x++) {
                        for (int y = -1; y <= 1; y++) {
                            if (x == 0 && y == 0 || x != 0 && y != 0) {
                                continue;
                            }
                            try {
                                if (maz[op.r + x][op.c + y] == ' ') {
                                    continue;
                                }
                            } catch (Exception e) {
                                continue;
                            }
                            frontier.add(new Point(op.r + x, op.c + y, op));
                        }
                    }
                }
            } catch (Exception e) { // ignore NullPointer and ArrayIndexOutOfBounds
            }

            // if algorithm has resolved, mark end node
            if (frontier.isEmpty()) {
                maz[last.r][last.c] = 'E';
            }
        }

        // print final maze
        for (int i = 0; i < r; i++) {
            for (int j = 0; j < c; j++) {
                System.out.print(maz[i][j]);
            }
            System.out.println();
        }
    }

    static class Point {

        Integer r;
        Integer c;
        Point parent;

        public Point(int x, int y, Point p) {
            r = x;
            c = y;
            parent = p;
        }

        // compute opposite node given that it is in the other direction from the parent
        public Point opposite() {
            if (this.r.compareTo(parent.r) != 0) {
                return new Point(this.r + this.r.compareTo(parent.r), this.c, this);
            }
            if (this.c.compareTo(parent.c) != 0) {
                return new Point(this.r, this.c + this.c.compareTo(parent.c), this);
            }
            return null;
        }
    }
}



Resultado:

Distancia entre 2 puntos en un espacio n-dimensional.

Fórmula:

 
d(P,Q) = SQRT[ (Q1-P1)^2 + (Q2-P2)^2 + (Q3-P3)^2 + ... + (Qn-Pn)^2 ]


Código java (Distancia2p.java)

package distancia2p;

import java.util.Arrays;

public class Distancia2p {

    public static void main(String[] args) {

        int n = 6;  //numero de dimensiones
        int[] A = new int[n];
        int[] B = new int[n];

        //posición cartesiana n coordenadas
        int maximo = 100;
        int minimo = 1;
        for (int i = 0; i < n; i++) {
            //numero aleatoria entre 1 (minimo) y 100 (maximo)
            A[i] = (int) Math.floor(Math.random() * (maximo - minimo + 1)) + minimo;
            B[i] = (int) Math.floor(Math.random() * (maximo - minimo + 1)) + minimo;
        }

        double aux = 0;
        double distancia;

        for (int i = 0; i < n; i++) {
            aux = aux + Math.pow((A[i] - B[i]), 2);
        }
        distancia = Math.sqrt(aux);

        //mostrar resultados
        System.out.println("*Distancia entre 2 puntos en un espacio de " + n + "-dimensiones:");
        System.out.println("coordenadas punto A: " + Arrays.toString(A));
        System.out.println("coordenadas punto B: " + Arrays.toString(B));
        System.out.println("Distancia entre punto A y B: " + distancia);

    }

}


Resultado:

run:
*Distancia entre 2 puntos en un espacio de 6-dimensiones:
coordenadas punto A: [29, 89, 69, 33, 18, 22]
coordenadas punto B: [76, 93, 41, 53, 43, 91]
Distancia entre punto A y B: 93.78166132032425
BUILD SUCCESSFUL (total time: 0 seconds)

Gráficos 2D. Creación de un fractal 2 (árbol).

Código 1: (Blogspot_Fractal.java):

package blogspot_fractal;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Blogspot_Fractal {

    public static void main(String[] args) {

        int x = 300;
        int y = 256;
        int angulo = -90;
        int depth = 9;

        BufferedImage imagen = new BufferedImage(x, y, BufferedImage.TYPE_INT_RGB);
        Dibujo.Dibujar((Graphics2D) imagen.getGraphics(), x / 2, y, angulo, depth);

        try {
            ImageIO.write(imagen, "png", new File("Arbol.png"));
        } catch (IOException e) {
            System.out.println("Error de escritura");
        }

    }

}


Código 2: (Dibujo.java):

package blogspot_fractal;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;

class Dibujo {

    public static void Dibujar(Graphics2D g, int x1, int y1, double angle, int depth) {

        if (depth == 0) {
            return;
        }
        
        g.setColor(Color.GREEN);
        
        // grosor rama dependiendo de la profundidad
        g.setStroke(new BasicStroke((float) depth));

        //Filtro antialiasing       
        g.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);

        int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 5.0);
        int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 6.0);
        g.drawLine(x1, y1, x2, y2);
        Dibujar(g, x2, y2, angle - 30, depth - 1);
        Dibujar(g, x2, y2, angle + 30, depth - 1);

    }

}


Resultado:

Graficos 2D. Curva de Hilbert 2 (4K)

Código 1: (Blogspot_Curvahilbert.java)

package blogspot_curvahilbert;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Blogspot_CurvaHilbert {

    public static void main(String[] args) {

        // resolucion 4K
        int x = 2160;
        int y = 2160;
        int depth = 8;

        BufferedImage imagen = new BufferedImage(x, y, BufferedImage.TYPE_INT_RGB);

        Dibujo.Dibujar((Graphics2D) imagen.getGraphics(), x / 2, y / 2, depth, y / 2);

        try {
            ImageIO.write(imagen, "png", new File("CurbaHilbert.png"));
        } catch (IOException e) {
            System.out.println("Error de escritura");
        }

    }

}


Código 2: (Dibujo.java):

package blogspot_curvahilbert;

import java.awt.Color;
import java.awt.Graphics2D;

class Dibujo {

    public static void Dibujar(Graphics2D g, int x, int y, int n, int size) {

        if (n == 0) {
            return;
        }

        int x0 = x - size / 2;
        int x1 = x + size / 2;
        int y0 = y - size / 2;
        int y1 = y + size / 2;
        g.setColor(Color.GREEN);
        g.drawLine(x0, y0, x0, y1);
        g.drawLine(x1, y0, x1, y1);
        g.drawLine(x0, y, x1, y);
        Dibujar(g, x0, y0, n - 1, size / 2);
        Dibujar(g, x0, y1, n - 1, size / 2);
        Dibujar(g, x1, y0, n - 1, size / 2);
        Dibujar(g, x1, y1, n - 1, size / 2);

    }

}

Resultado: