// This class contains several small examples of array manipulation.  Each is
// written as a method.  The main method includes some sample client code.

import java.util.*;

public class ArraySample3 {
    public static void main(String[] args) {
        int[] list1 = {12, 8, 4, 0, 208, 14, 42, 38, 72, 96, 102};
        int[] list2 = {84, 42, 92, 96, 2, 4, 8, 0, 72, 302, 17, 408};

        System.out.println("list1 = " + Arrays.toString(list1));
        System.out.println("list2 = " + Arrays.toString(list2));

        System.out.println("allEven(list1) returns " + allEven(list1));
        System.out.println("allEven(list2) returns " + allEven(list2));

        System.out.println("indexOf(list1, 42) returns " + indexOf(list1, 42));
        System.out.println("indexOf(list1, 16) returns " + indexOf(list1, 16));
        System.out.println("indexOf(list2, 42) returns " + indexOf(list2, 42));
        System.out.println("indexOf(list2, 16) returns " + indexOf(list2, 16));

        int[] sum = runningSum(list1);
        System.out.println("runningSum(list1) returns " +
                           Arrays.toString(sum));
        sum = runningSum(list2);
        System.out.println("runningSum(list2) returns " +
                           Arrays.toString(sum));

        System.out.println("result of rotating left:");
        System.out.println("    list1 = " + Arrays.toString(list1));
        for (int i = 0; i < list1.length; i++) {
            rotateLeft(list1);
            System.out.println("    list1 = " + Arrays.toString(list1));
        }     
                
        System.out.println("result of rotating right:");
        System.out.println("    list2 = " + Arrays.toString(list2));
        for (int i = 0; i < list2.length; i++) {
            rotateRight(list2);
            System.out.println("    list2 = " + Arrays.toString(list2));
        }

        System.out.println("list1 before sort = " + Arrays.toString(list1));
        gnomeSort(list1);
        System.out.println("list1 after sort  = " + Arrays.toString(list1));
    }

    // Write a static method called allEven that takes an array of integers as
    // a parameter and that returns true if all the integers are even and that
    // returns false otherwise
    public static boolean allEven(int[] list) {
        for (int i = 0; i < list.length; i++) {
            if (list[i] % 2 != 0) {
                return false;
            }
        }
        return true;
    }

    // Write a static method called indexOf that takes an array of integers and
    // a value as parameters and that returns the index of the first occurrence
    // of the value in the array, returning -1 if not found
    public static int indexOf(int[] list, int target) {
        for (int i = 0; i < list.length; i++) {
            if (list[i] == target) {
                return i;
            }
        }
        return -1;
    }

    // Write a static method called runningSum that takes an array of integers
    // as a parameter and that returns a new array that contains the running
    // sum of the numbers in the array (where the i-th value of the new array
    // is the sum of the first i values of the original array)
    public static int[] runningSum(int[] list) {
        int[] result = new int[list.length];
        if (list.length > 0) {
            result[0] = list[0];
            for (int i = 1; i < list.length; i++) {
                result[i] = list[i] + result[i - 1];
            }
        }
        return result;
    }

    // Write a static method called rotateLeft that takes an array of integers
    // as a parameter and that rotates all values to the left by one position,
    // rotating the first value to the back of the array.  For example, given
    // the list {1, 2, 3, 4}, a call on rotateLeft should yield {2, 3, 4, 1}.
    public static void rotateLeft(int[] list) {
        int temp = list[0];
        for (int i = 0; i < list.length - 1; i++) {
            list[i] = list[i + 1];
        }
        list[list.length - 1] = temp;
    }

    // Write a static method called rotateRight that takes an array of integers
    // as a parameter and that rotates all values to the right by one position,
    // rotating the last value to the front of the array (e.g., given the list
    // {1, 2, 3, 4}, a call on rotateRight should yield the list {4, 1, 2, 3})
    public static void rotateRight(int[] list) {
        int temp = list[list.length - 1];
        for (int i = list.length - 2; i >= 0; i--) {
            list[i + 1] = list[i];
        }
        list[0] = temp;
    }

    // In the 11:30 lecture, the following method was discussed.  It sorts an
    // array of ints.
    public static void gnomeSort(int[] list) {
        int i = 0;
        while (i < list.length - 1) {
            if (list[i] <= list[i + 1]) {
                i++;
            } else {
                int temp = list[i];
                list[i] = list[i + 1];
                list[i + 1] = temp;
                if (i > 0) {
                    i--;
                }
            }
        }
    }
}