ArraysTask1FrequentElemFinder.java

package HomeWorkSecond;

/**
 * Created by Andrey on 10.01.2016.
 */
public class ArraysTask1FrequentElemFinder {
    public static void main(String[] args) {
        int[] array = {1, 2, 1, 0, 3};
        System.out.print(findFrequentElem(array));
    }

    public static int findFrequentElem(int[] array) {
        int result = 0;
        int maxIndex = 0;
        for (int i : array) {
            int count = 0;
            for (int j : array) {
                if (i == j) {
                    count++;
                }
                if (maxIndex < count) {
                    maxIndex = count;
                    result = i;
                }
            }
        }
        return result;
    }
}

ArraysTask2CyclicShifter.java

package HomeWorkSecond;

/**
 * Created by Andrey on 11.01.2016.
 */
public class ArraysTask2CyclicShifter {
    public static void main(String[] args) {
        int[] array = {0, 1, 2, 3, 4};
        int shiftPosition = 1;
        cyclicShift(array, shiftPosition);
    }

    public static void cyclicShift(int[] array, int shiftPozition) {
        int[] reloadArray = new int[array.length];
        int reload = array.length - 1;
        while (shiftPozition < 0) {
            shiftPozition += array.length;
        }
        while (shiftPozition > reload) {
            shiftPozition -= array.length;
        }
        reload = shiftPozition;

        for (int i : array) {
            if (reload > array.length - 1) reload = 0;
            reloadArray[reload] = i;
            reload++;
        }
        for (int j : reloadArray) {
            System.out.print(j + ", ");
        }
    }
}

ArraysTask3SpiralCreator.java

package HomeWorkSecond;

/**
 * Created by Andrey on 12.01.2016.
 */
public class ArraysTask3SpiralCreator {

    public static void main(String[] args) {

        int rows = 7;
        int cols = 8;
        int[][] array = createSpiral(rows, cols);
    }

    public static int[][] createSpiral(int rows, int cols) {
        checker(rows, cols);
        int[][] array = new int[rows][cols];
        madeSpiralArray(array);
        printArray(array);
        return array;
    }

    public static void madeSpiralArray(int[][] array) {
        int indexCols = 0;
        int indexRows = 0;
        int lengthRows = array.length - 1;
        int lengthCols = array[0].length - 1;
        int digitResult = ((lengthCols + 1) * (lengthRows + 1));
        int modulus = 0;
        int count = 1;
        while (count < digitResult) {
            for (int i = indexCols + modulus; i < lengthCols - modulus; i++) {
                array[indexRows + modulus][i] = count;
                count++;
            }
            for (int i = indexRows + modulus; i < lengthRows - modulus; i++) {
                array[i][lengthCols - modulus] = count;
                count++;
            }
            for (int i = lengthCols - modulus; i > indexCols + modulus; i--) {
                array[lengthRows - modulus][i] = count;
                count++;
            }
            for (int i = lengthRows - modulus; i > indexRows + modulus; i--) {
                array[i][indexCols + modulus] = count;
                count++;
            }
            if (lengthRows % 2 == 0 && lengthCols % 2 == 0 && lengthCols == lengthRows)
                array[lengthRows / 2][lengthRows / 2] = digitResult;
            modulus++;
        }
        return;
    }

    public static void checker(int rows, int cols) {
        if (rows <= 0 || cols <= 0) throw new IllegalArgumentException(" rows or cols is less then one ");
    }

    public static void printArray(int[][] array) {
        for (int[] i : array) {
            for (int j : i) {
                System.out.print(j + "\t");
            }
            System.out.println();
        }
    }
}

ArraysTask4PascalTriangleCreator.java

package HomeWorkSecond;

/**
 * Created by Andrey on 15.01.2016.
 */
public class ArraysTask4PascalTriangleCreator {
    public static void main(String[] args) {
        int n = 2;
        createPascalTriangle(n);
    }

    public static int[][] createPascalTriangle(int n) {
        check(n);
        int rows = n + 1;
        int[][] triangle = new int[rows][rows];
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < i + 1; j++) {
                if (j == 0) {
                    triangle[i][j] = 1;
                    System.out.print(triangle[i][j] + "\t");
                } else {
                    triangle[i][j] = triangle[i - 1][j] + triangle[i - 1][j - 1];
                    System.out.print(triangle[i][j] + "\t");
                }
            }
            System.out.println();
        }
        return triangle;
    }

    public static void check(int n) {
        if (n < 0) throw new IllegalArgumentException(" Your numb is less then zero :");
    }
}

ArraysTask5MatrixPacking.java

package HomeWorkSecond;

/**
 * Created by Andrey on 19.01.2016.
 */
public class ArraysTask5MatrixPacking {
    public static void main(String[] args) {
        int[][] array = {{1, 2, 3}, {0, 0, 0}, {4, 5, 6}};
        packMatrix(array);
    }

    public static int[][] packMatrix(int[][] array) {
        int[][]packMatrix;
        int indexRows = indexRowsFinder(array);
        int indexCols = indexColsFinder(array);
        packMatrix = new int[indexRows][indexCols];
        packMatrix = arrayToPackMatrixWriter(array, indexCols, packMatrix);
        print(packMatrix);
        return array;
    }

    public static int [][] arrayToPackMatrixWriter(int[][] array, int indexCols, int[][] packMatrix) {
        int cols = 0;
        int rows = 0;
        for (int i = 0; i < array[0].length; i++) {
            for (int j = 0; j < array.length; j++) {
                if (array[i][j] > 0) {
                    packMatrix[rows][cols] = array[i][j];
                    cols++;
                    cols = checkCols(indexCols, cols);
                    rows = rowPlus(cols, rows);
                }
            }
        }return packMatrix;
    }

    public static void print(int[][] array) {
        for (int[] i : array) {
            for (int j : i) {
                System.out.print(j + "\t");
            }
            System.out.println();
        }
    }

    public static int rowPlus(int cols, int rows) {
        if (cols == 0) {
            rows++;
        } return rows;
    }

    public static int checkCols(int indexCols, int cols) {
        if (cols == indexCols) {
            cols = 0;
        }
        return cols;
    }

    public static int indexColsFinder(int[][] array) {
        int indexCols = 0;
        for (int i = 0; i < array[0].length; i++) {
            int count = 0;
            for (int j = 0; j < array.length; j++) {
                count = indexMaker(array[i][j], count);
            }
            indexCols = count;
        }
        return indexCols;
    }

    public static int indexRowsFinder(int[][] array) {
        int indexRows = 0;
        for (int i = 0; i < array[0].length; i++) {
            int indexCols = 0;
            for (int j = 0; j < array.length; j++) {
                indexCols = indexMaker(array[i][j], indexCols);
            }
            indexRows = indexMaker(indexCols, indexRows);
        }
        return indexRows;
    }

    public static int indexMaker(int i, int index) {
        if (i > 0) index++;
        return index;
    }
}