Counting Sort Java Program Logic

Hey guys in this post, we will discuss the most popular sorting algorithm that is Counting sort in Java language.

``````class CountingSort
{
void sort(char arr[])
{
int n = arr.length;

// The output character array that will have sorted arr
char output[] = new char[n];

// Create a count array to store count of inidividul
// characters and initialize count array as 0
int count[] = new int[256];
for (int i=0; i<256; ++i)
count[i] = 0;

// store count of each character
for (int i=0; i<n; ++i)
++count[arr[i]];

// Change count[i] so that count[i] now contains actual
// position of this character in output array
for (int i=1; i<=255; ++i)
count[i] += count[i-1];

// Build the output character array
for (int i = 0; i<n; ++i)
{
output[count[arr[i]]-1] = arr[i];
--count[arr[i]];
}

// Copy the output array to arr, so that arr now
// contains sorted characters
for (int i = 0; i<n; ++i)
arr[i] = output[i];
}

// Driver method
public static void main(String args[])
{
CountingSort ob = new CountingSort();
char arr[] = {'g', 'e', 'e', 'k', 's', 'f', 'o',
'r', 'g', 'e', 'e', 'k', 's'
};

ob.sort(arr);

System.out.print("Sorted character array is ");
for (int i=0; i<arr.length; ++i)
System.out.print(arr[i]);
}
}
``````

Output:

``````Sorted character array is eeeefggkkorss
``````

That’s it for this post, if you like this post, share this with your friends and colleagues or you can share this within your social media platform. Thanks, I will see you in our next post.

Bushan Sirgur

Hey guys, I am Bushan Sirgur from Banglore, India. Currently, I am working as an Associate project in an IT company.