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Merged
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Aug 19, 2017
Merged

Update BinarySearch.java #82

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123 changes: 63 additions & 60 deletions Searches/BinarySearch.java
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Original file line number Diff line number Diff line change
@@ -1,68 +1,71 @@
import java.util.Scanner;

/**
* Implements a Binary Search in Java
*
* @author unknown
* @author Varun Upadhyay (https://github.com/varunu28)
*
*/

class BinarySearch
{
/**
* This method implements the Binary Search
*
* @param array The array to make the binary search
* @param key The number you are looking for
* @param lb The lower bound
* @param up The upper bound
* @return the location of the key
**/
public static int BS(int array[], int key, int lb, int ub)
{
if ( lb > ub)
return -1;

int mid = (lb + ub) / 2;

if (key < array[mid])
return (BS(array, key, lb, mid-1));

if (key > array[mid])
return (BS(array, key, mid + 1, ub));

return mid;
}


/**
* This is the main method of Binary Search
*
* @author Unknown
* @param args Command line parameters
*/

public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
int array[]=new int[10] ;
int key;

//Input
System.out.println("Enter an array of 10 numbers : ");

for (int i = 0; i < 10 ; i++ )
array[i] = input.nextInt();

System.out.println("Enter the number to be searched : ");

key = input.nextInt();

int index=BS(array, key, 0, 9);

if (index != -1)
System.out.println("Number found at index number : " + index);
else
System.out.println("Not found");

input.close();
}
/**
* This method implements the Generic Binary Search
*
* @param array The array to make the binary search
* @param key The number you are looking for
* @param lb The lower bound
* @param ub The upper bound
* @return the location of the key
**/

public static <T extends Comparable<T>> int BS(T array[], T key, int lb, int ub)
{
if ( lb > ub)
return -1;

int mid = (ub+lb)/2;
int comp = key.compareTo(array[mid]);

if (comp < 0)
return (BS(array, key, lb, mid-1));

if (comp > 0)
return (BS(array, key, mid + 1, ub));

return mid;
}

// Driver Program
public static void main(String[] args)
{
Scanner input=new Scanner(System.in);

// For INTEGER Input
Integer[] array = new Integer[10];
int key = 5;

for (int i = 0; i < 10 ; i++ )
array[i] = i+1;

int index = BS(array, key, 0, 9);

if (index != -1)
System.out.println("Number " + key + " found at index number : " + index);
else
System.out.println("Not found");


// For STRING Input
String[] array1 = {"a", "b", "c", "d", "e"};
String key1 = "d";

int index1 = BS(array1, key1, 0, array1.length-1);

if (index1 != -1)
System.out.println("String " + key1 + " found at index number : " + index1);
else
System.out.println("Not found");

input.close();
}
}