Create Radix sort.java

Sorting Algorithms/Java/Radix sort.java

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+// Radix sort Java implementation
+
+import java.io.*;
+import java.util.*;
+
+class Radix {
+
+	// A utility function to get maximum value in arr[]
+	static int getMax(int arr[], int n)
+	{
+		int mx = arr[0];
+		for (int i = 1; i < n; i++)
+			if (arr[i] > mx)
+				mx = arr[i];
+		return mx;
+	}
+
+	// A function to do counting sort of arr[] according to
+	// the digit represented by exp.
+	static void countSort(int arr[], int n, int exp)
+	{
+		int output[] = new int[n]; // output array
+		int i;
+		int count[] = new int[10];
+		Arrays.fill(count, 0);
+
+		// Store count of occurrences in count[]
+		for (i = 0; i < n; i++)
+			count[(arr[i] / exp) % 10]++;
+
+		// Change count[i] so that count[i] now contains
+		// actual position of this digit in output[]
+		for (i = 1; i < 10; i++)
+			count[i] += count[i - 1];
+
+		// Build the output array
+		for (i = n - 1; i >= 0; i--) {
+			output[count[(arr[i] / exp) % 10] - 1] = arr[i];
+			count[(arr[i] / exp) % 10]--;
+		}
+
+		// Copy the output array to arr[], so that arr[] now
+		// contains sorted numbers according to current
+		// digit
+		for (i = 0; i < n; i++)
+			arr[i] = output[i];
+	}
+
+	// The main function to that sorts arr[] of
+	// size n using Radix Sort
+	static void radixsort(int arr[], int n)
+	{
+		// Find the maximum number to know number of digits
+		int m = getMax(arr, n);
+
+		// Do counting sort for every digit. Note that
+		// instead of passing digit number, exp is passed.
+		// exp is 10^i where i is current digit number
+		for (int exp = 1; m / exp > 0; exp *= 10)
+			countSort(arr, n, exp);
+	}
+
+	// A utility function to print an array
+	static void print(int arr[], int n)
+	{
+		for (int i = 0; i < n; i++)
+			System.out.print(arr[i] + " ");
+	}
+
+	// Main driver method
+	public static void main(String[] args)
+	{
+		int arr[] = { 170, 45, 75, 90, 802, 24, 2, 66 };
+		int n = arr.length;
+
+		// Function Call
+		radixsort(arr, n);
+		print(arr, n);
+	}
+}