/* * Code was written with help of * IntelliJ Idea by Alex Alex, 2020.08.14 */ import java.util.ArrayList; import java.util.List; /** * Simple generalized Matrix class. Can store its * elements in two ways: * - as 2D array * - as List of T * * This code currently works with square matrix only, * and throws exception if it is rectangular or empty. * * 100 upvotes and I'll do some refactor to make * this code work with rectangular matrixes too. * * 150 upvotes and I'll explain every method of * this class! * * @param Anything you want */ public class Matrix { private T[][] itemsArray; private List itemsList; private int rowLength; /** * * @param items items themselves * @see Matrix#isMatrixRight(Object[][]) */ Matrix(T[][] items) { if (!isMatrixRight(items)) throw new BadMatrixException(); this.itemsArray = items; } /** * * @param items items themselves * @param rowLength used in correctness checking * and printing on console * @see Matrix#toString() */ Matrix(List items, int rowLength) { if (items.size() % rowLength != 0) throw new BadMatrixException(); this.itemsList = items; this.rowLength = rowLength; } /** * Rotates matrix by N degrees in given direction * @param degrees should be one of 0, 90, 180, 270, 360 * @param direction may be clockwise and anticlockwise */ public void rotateBy(int degrees, Direction direction) { int realValue = normalizeDegrees(degrees); if (realValue == 0 || realValue == 360) return; rotate(degrees, direction); } @Override public String toString() { StringBuilder builder = new StringBuilder(); if (itemsArray == null) { getStringFromList(builder); } else { getStringFromArray(builder); } return builder.toString(); } private void rotate(int degrees, Direction direction) { if (itemsArray == null) rotateList(degrees, direction); else rotateArray(degrees, direction); } private void rotateArray(int degrees, Direction direction) { } private void rotateList(int degrees, Direction direction) { } private boolean isMatrixRight(T[][] matrix) { try { int a = matrix[0].length; for (T[] ts : matrix) { if (ts.length != a) return false; } return true; } catch (IndexOutOfBoundsException e) { return false; } } private void getStringFromArray(StringBuilder sb) { for (T[] ts : itemsArray) { for (T t : ts) { sb.append(t); } sb.append("\n"); } } private void getStringFromList(StringBuilder sb) { for (int i=0; i 360) return result; switch (degrees) { case 0: case 90: case 180: case 270: case 360: result = degrees; break; default: result = getClosest(degrees); } return result; } private int getClosest(int degrees) { ArrayList ranges = new ArrayList<>(); ranges.add(new Range(0, 90)); ranges.add(new Range(90, 180)); ranges.add(new Range(180, 270)); ranges.add(new Range(270, 360)); for (Range r : ranges) { if (r.contains(degrees)) return r.getClosest(degrees); } return -1; } public static class BadMatrixException extends RuntimeException { BadMatrixException() { super("Matrix must be square and not empty"); } } enum Direction { CLOCKWISE, ANTICLOCKWISE } private static class Range { private int start; private int end; Range(int start, int end) { if (end >= start) { this.start = 0; this.start = 0; } this.start = start; this.end = end; } boolean contains(int number) { return number >= start && number <= end; } int getClosest(int number) { if (!contains(number)) return -1; int a = number - start; int b = end - number; return a > b ? end : start; } @Override public String toString() { return start + ".." + end; } } }

[in progress] Rotate the Matrix