Daily Archives: August 4, 2016

Search

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Binary search is faster then linear search if the collection is sorted and does not contains duplicated Values

public static void BinarySearch(int searchVal)
{
  int lowerIndex = 0;
  int higherIndex = arrNumbers.length;
  int searchIndex = 0;
  
  while(lowerIndex < higherIndex)
  {
	int middleIndex = (lowerIndex + higherIndex)/2;
	
	if(searchVal < arrNumbers[middleIndex])
	{
		higherIndex = middleIndex + 1; 
	}
	else if(searchVal > arrNumbers[middleIndex])
	{
		lowerIndex = middleIndex - 1;
	}  
	else
	{
		searchIndex = middleIndex+1;			
		System.out.println("The element is Found at Index " + searchIndex);
		return;
	}
  }
}

Sorting

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Bubble Sort

public void bubbleSort()
{
	for (int i = arrNumbers.length-1; i>1 ; i--) 
	{	
		for (int j = 0; j < i; j++) 
		{			
			if(arrNumbers[j] > arrNumbers[j+1])
			{
				swapValuesAtIndex(j, j+1);					
			}
			
			/*IterationDisplay(arrNumbers, j);*/
		}
	}
}

Selection Sort
Selection sort works by dividing the list into 2 Parts. Sorted and Unsorted.Taking one element at a time as Minimum element it works by comparing the minimum element with other elements in the list.

public void selectionSort()
{
	int minElement = 0;
	
	for (int i = 0; i< arrNumbers.length ; i++) 
	{
     	minElement = i;
		
		for (int j = i; j < arrNumbers.length; j++) 
		{			
			if(arrNumbers[minElement] > arrNumbers[j])
			{						
				minElement =  j;
			}
		}
		
		swapValuesAtIndex(minElement, i);
	}
}

Insertion Sort
Insertion sort is the best sorting method compared to others.The list is divided into sorted and unsorted portion. Once a no is selected for comparison it will not ened without placing the no at the correct location.

public void insertionSort()
{	
	for (int i = 1; i < arrNumbers.length; i++) 
	{
		int j = i;
		int toCompare = arrNumbers[i];
		
		//holds no to Insert - arrNumbers[j-1]
		while((j>0) && (arrNumbers[j-1] > toCompare))
		{
			arrNumbers[j] = arrNumbers[j-1];
			j--;
		}
		
		arrNumbers[j] =  toCompare;		
	}
}

Algorithms FAQ

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  1. Linear search is faster when searching for a element in a collection where the elements are duplicated and occurs multiple time. Binary Search is efficient when the collection elements are unique

How to Remove element from array

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public static String[] removeElements(String[] input, String deleteMe) 
{
    List result = new LinkedList();

    for(String item : input)
        if(!deleteMe.equals(item))
            result.add(item);

    return result.toArray(input);
}