Daily programmer challenge n. 337 - https://www.reddit.com/r/dailyprogrammer/comments/78twyd/20171026_challenge_337_intermediate_scrambled/

challenge337.java

package com.jakublesko;

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

public class Challenge337 {

    private BufferedImage sourceImage;
    private BufferedImage targetImage;

    private int imageWidth;
    private int imageHeight;

    private Challenge337(String filename) {
        loadImage(filename);
        processImage();
        renderImage();
    }

    private void processImage() {
        if (sourceImage == null) {
            System.err.println("No image for processing!");
            return;
        }

        targetImage = new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_ARGB);

        for (int row = 0; row < imageHeight; row++) {
            int[] orderedRow = new int[imageWidth];
            int redPosition = 399;

            for (int col = 0; col < imageWidth; col++) {
                int aRGB  = sourceImage.getRGB(col, row);
                int red   = (aRGB >> 16) & 0xFF;
                int green = (aRGB >> 8) & 0xFF;
                int blue  = (aRGB) & 0xFF;

                orderedRow[col] = aRGB;

                if (red == 255 && green == 0 && blue == 0) {
                    redPosition = col + 1;
                }
            }

            for (int i = 0; i < imageWidth - redPosition; i++) {
                for (int j = orderedRow.length - 1; j > 0; j--) {
                    int temp = orderedRow[j];
                    orderedRow[j] = orderedRow[j - 1];
                    orderedRow[j - 1] = temp;
                }
            }

            for (int col = 0; col < imageWidth; col++) {
                targetImage.setRGB(col, row, orderedRow[col]);
            }
        }
    }

    private void loadImage(String fileName) {
        try {
            sourceImage = ImageIO.read(new File(fileName));
            imageWidth = sourceImage.getWidth();
            imageHeight = sourceImage.getHeight();
        } catch (IOException exception) {
            System.err.println("Error reading image file from disk!\n" + exception);
        }
    }

    private void renderImage() {
        if (targetImage == null) {
            System.err.println("No image for rendering!");
            return;
        }

        try {
            ImageIO.write(targetImage, "png", new File("output.png"));
        } catch (IOException exception) {
            System.err.println("Error writing image file to disk!\n" + exception);
        }
    }

    public static void main(String[] args) {
        new Challenge337("input01.png");
    }
}