Lessons5Example1Level2

package com.gmail.kudr641;

import java.util.Arrays;
import java.util.Scanner;

public class Lessons5Example1Level2 {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		System.out.println("Enter the sequence length");

		int lenth = scanner.nextInt();

		System.out.println("Enter number:");
		int[] array = new int[lenth];
		for (int i = 0; i < array.length; i += 1) {
			array[i] = scanner.nextInt();
		}

		scanner.close();

		if (ifArithmeticalProgression(array)) {
			printResultArithmeticalProgression(array);
		} else if (ifQeometricProgression(array)) {
			printResultQeometricProgression(array);
		} else if (ifExponentTwoProgression(array)) {
			printResultExponentTwoProgression(array);
		} else if (ifExponentThreeProgression(array)) {
			printResultExponentThreeProgression(array);
		}
	}

	static boolean ifArithmeticalProgression(int[] array) {
		boolean result = false;
		int[] additionalArray = new int[array.length - 1];

		for (int i = 0; i < array.length - 1; i += 1) {
			additionalArray[i] = (array[i + 1] - array[i]);
		}

		for (int i = 0; i < additionalArray.length - 1; i += 1) {
			if (additionalArray[i] == additionalArray[i + 1]) {
				result = true;
			} else {
				result = false;
				break;
			}
		}
		return result;
	}

	static boolean ifArithmeticalProgression(double[] array) {
		boolean result = false;
		int[] additionalArray = new int[array.length - 1];

		for (int i = 0; i < array.length - 1; i += 1) {
			additionalArray[i] = (int) (array[i + 1] - array[i]);
		}

		for (int i = 0; i < additionalArray.length - 1; i += 1) {
			if (additionalArray[i] == additionalArray[i + 1]) {
				result = true;
			} else {
				result = false;
				break;
			}
		}
		return result;
	}

	static void printResultArithmeticalProgression(int[] array) {
		int difference = array[array.length - 1] - array[array.length - 2];
		int outcome = array[array.length - 1] + difference;
		System.out.println(outcome);
	}

	static boolean ifQeometricProgression(int[] array) {
		boolean result = false;
		int[] additionalArray = new int[array.length - 1];

		for (int i = 0; i < array.length - 1; i += 1) {
			additionalArray[i] = (array[i + 1] / array[i]);
		}

		for (int i = 0; i < additionalArray.length - 1; i += 1) {
			if (additionalArray[i] == additionalArray[i + 1]) {
				result = true;
			} else {
				result = false;
				break;
			}
		}
		return result;
	}

	static void printResultQeometricProgression(int[] array) {
		int difference = array[array.length - 1] / array[array.length - 2];
		int outcome = array[array.length - 1] * difference;
		System.out.println(outcome);
	}

	static boolean ifExponentTwoProgression(int[] array) {
		int[] additionalArray = new int[array.length];

		for (int i = 0; i < array.length; i += 1) {
			additionalArray[i] = (int) Math.sqrt(array[i]);
		}
		return ifArithmeticalProgression(additionalArray);
	}

	static void printResultExponentTwoProgression(int[] array) {
		int[] additionalArray = new int[array.length];
		for (int i = 0; i < array.length; i += 1) {
			additionalArray[i] = (int) Math.sqrt(array[i]);
		}
		int outcome = (additionalArray[additionalArray.length - 1] + 1)
				* (additionalArray[additionalArray.length - 1] + 1);
		System.out.println(outcome);
	}

	static boolean ifExponentThreeProgression(int[] array) {
		double[] additionalArray = new double[array.length];

		for (int i = 0; i < array.length; i += 1) {
			additionalArray[i] = Math.ceil(sqrt(array[i], 3));			
		}		
		return ifArithmeticalProgression(additionalArray);
	}

	static void printResultExponentThreeProgression(int[] array) {
		double[] additionalArray = new double[array.length];
		for (int i = 0; i < array.length; i += 1) {
			additionalArray[i] = sqrt(array[i], 3);
		}
		double outcome = additionalArray[additionalArray.length - 1] + 1;
		System.out.println((int) Math.pow(outcome, 3));
	}

	static double sqrt(double x, double n) {
		return Math.pow(x, 1 / n);
	}
}

Lessons5Example2Level2

package com.gmail.kudr641;

public class Lessons5Example2Level2 {

	public static void main(String[] args) {
		int maxPolindrom = 0;

		for (int i = 100; i <= 999; i += 1) {
			for (int j = 100; j <= 999; j += 1) {
				int sum = i * j;

				String strSum = Integer.toString(sum);
				StringBuilder sb = new StringBuilder(strSum);

				if (strSum.equals(sb.reverse().toString()) && maxPolindrom < i * j) {

					maxPolindrom = Integer.parseInt(strSum);
				}
			}
		}
		System.out.println(maxPolindrom);
	}
}

Lessons5Example3Level2

package com.gmail.kudr641;

import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class Lessons5Example3Level2 {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		System.out.println("Input size array:");
		int size = scanner.nextInt();

		scanner.close();

		int[] array = new int[size];

		for (int i = 0; i < array.length; i += 1) {
			array[i] = i;
		}
		
		//int coint = 0; 
		getResult(array, 0);

	}

	static void getResult(int[] array, int i) {	
		if (i == array.length - 1) {			
			System.out.println(Arrays.toString(array));
			
		} else {
			for (int j = i; j < array.length; j += 1) {				
				int k = array[i];
				array[i] = array[j];
				array[j] = k;
				
				getResult(array, i + 1);
				
				k = array[i];
				array[i] = array[j];
				array[j] = k;
			}
		}
	}
}