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.

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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)

		// 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];

		// 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'


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


Sorted character array is eeeefggkkorss 

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About the author

Bushan Sirgur

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

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