CareerCup

Sample input:
This is a sample.This is a sample.This is a sample.This is a sample.
This is a sample.This is a sample.This is a sample.This is a sample. This
is a sample.This is a sample.This is a sample.This is a sample.This is a
sample.

Could you please explain what 'st' and 'en' mean? Also, if you could explain in brief about the methods, it'll be easier to follow.

Thanks!

Solution in Java:

public class FindElementInSortedRotatedArray {
    private static int findElement(int [] input, int target){
        if(input == null || input.length == 0){
            return -1;
        }

        int start = 0;
        int end = input.length - 1;
        int mid = (start + end)/2;

        for(int i = 0; i < input.length; i++){

            // check if start to mid of input array is sorted
            if(input[start] <= input[mid]){

                // check if target element lies between start and mid
                if(input[start] <= target && target <= input[mid]){

                    // if target lies with start and mid, set end pointer to mid-1
                    end = mid - 1;
                }
                else{
                    start = mid + 1;
                }
            }
            // then check if mid to end of input array is sorted
            else {
                if(input[mid] <= target && target <= input[end]){

                    // set start pointer to mid + 1
                    start = mid + 1;
                }
                else {
                    end = mid - 1;
                }

            }
        }
        return -1;
    }

    public static void main(String[] args) {
        {
            int array[] = { 56, 58, 67, 76, 21, 32, 37, 40, 45, 49 };
            findElementUsingBinarySearchTest(array, 45);
        }
    }

    private static void findElementUsingBinarySearchTest(int[] array, int num) {
        System.out.println("Element " + num + " found at = " + findElement(array, num));
    }
}

My solution in Java:

import java.util.Random;

public class ShuffleDeckOfCards {
    private static void shuffle(int[] input) {
        int inputLength = input.length;
        // class to generate random numbers
        Random r = new Random();

        for (int i = inputLength - 1; i > 0; i--) {
            // Generate random index
            int index = r.nextInt(i);

            // swap i with randomly generated index
            int temp = input[index];
            input[index] = input[i];
            input[i] = temp;
        }
    }

    public static void main(String[] args) {
        int[] cards = new int[52];
        for (int i = 0; i < 52; i++) {
            cards[i] = i + 1;
        }
        shuffle(cards);
    }
}

// Time complexity: O(N)

public class Attempt1{
    boolean[] row = new boolean[n];
    boolean[] column = new boolean[n];
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (matrix[i][j] == "x") {
                row[i] = true;
                column[j] = true;
            }
        }
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (row[i] || column[j]) {
                matrix[i][j] = "x";
            }
        }
    }
    System.out.println("Resultant matrix: ");
    printMatrix(matrix, n);
    return matrix;
}

Here are my questions: 1. Is there a better way to solve this? 2. Should I consider a better data structure?

Thank you.