‪#‎Javafest_Brain_Tweaker‬ # 1 Link: https://www.facebook.com/therapjavafest/posts/591777984278321

Find Sub Array

Problem Statement
-----------------------------

Find an Array:

Implement a method that given two arrays as parameters will find the starting index where the second parameter occurs as a sub-array in the array given as the first parameter.
Your implementations should return -1 if the sub-array cannot be found.

Your implementation must implement the FindArray interface given bellow:

public interface FindArray 
{
  int findArray(int[] array, int[] subArray);
}


Sample Input:

[4,9,3,7,8] and [3,7] should return 2.
[1,3,5] and [1] should return 0.
[7,8,9] and [8,9,10] should return -1.


Sample Code :

public class MyFindArray implements FindArray 
{
  public int findArray(int[] array, int[] subArray) 
  {
    return -1;
  }
}

FindArray.java

public interface FindArray 
{
	int findArray(int[] array, int[] subArray);
}

MyFindArray.java

/**
 * @author Al- Imran Ahmed
 * @date 16th October 20014
 */
 
import java.util.Arrays;

public class MyFindArray implements FindArray
{
  
	@Override
	public int findArray(int[] array, int[] subArray) 
	{
		int arrayLength = array.length;
		int subArrayLength = subArray.length;
		boolean hasSubArray = true;
		
		if(subArrayLength < arrayLength)//sub array is smaller than main array
		{
			for(int i = 0; i < arrayLength; i++)
			{
				if(arrayLength - i >= subArrayLength)
				{
					int[] tempArray = Arrays.copyOfRange(array, i, i+subArrayLength);
					//System.out.println(Arrays.toString(tempArray));
					if(Arrays.equals(tempArray, subArray)) return i;
					else hasSubArray = false;
				}
				else return -1;
			}
			if(!hasSubArray) return -1; //when no matching found
		}
		else if(subArrayLength == arrayLength)//else when the length of sub array is equal the length of main array
		{
			return Arrays.equals(subArray, array) ?  0 : -1;
		}
		return -1;
	}
	
	//Main method
	public static void main(String[] CHAND)
	{
		MyFindArray objFindArray = new MyFindArray();
        int[] array = {4, 9, 3, 7, 8};
        int[] sub_array = {7, 8};
        System.out.println(objFindArray.findArray(array, sub_array));
	}
}