Merge pull request codemistic#580 from s-a-c-h-i-n/main

Radix sort implementation in java

Author: gantavyamalviya

Java/RadixSort.java

@@ -0,0 +1,80 @@
+// 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);
+}
+}