Merge pull request #5 from pojith/pojith-patch-5

 radix sort

Author: pojith

Java/Algorithm/SortingAlgorithm/radix sort

@@ -0,0 +1,86 @@
+import java.util.Arrays;
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class RadixSort {
+
+    // Function to find the maximum element in the array
+    public static int getMax(int[] arr) {
+        int max = arr[0];
+        for (int i = 1; i < arr.length; i++) {
+            if (arr[i] > max) {
+                max = arr[i];
+            }
+        }
+        return max;
+    }
+
+    // A function to do counting sort of arr[] according to the digit represented by exp
+    public static void countSort(int[] arr, int exp) {
+        int n = arr.length;
+        int[] output = new int[n]; // output array
+        int[] count = new int[10];
+        Arrays.fill(count, 0);
+
+        // Store count of occurrences in count[]
+        for (int 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 (int i = 1; i < 10; i++) {
+            count[i] += count[i - 1];
+        }
+
+        // Build the output array
+        for (int 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 the current digit
+        System.arraycopy(output, 0, arr, 0, n);
+    }
+
+    // The main function to that sorts arr[] of size n using Radix Sort
+    public static void radixSort(int[] arr) {
+        int max = getMax(arr);
+
+        // Do counting sort for every digit.
+        // Instead of passing digit number, exp is passed. exp is 10^i where i is the current digit number
+        for (int exp = 1; max / exp > 0; exp *= 10) {
+            countSort(arr, exp);
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        try {
+            System.out.print("Enter the number of elements: ");
+            int n = scanner.nextInt();
+            if (n <= 0) {
+                throw new IllegalArgumentException("Number of elements must be positive.");
+            }
+
+            int[] arr = new int[n];
+
+            System.out.println("Enter the elements:");
+            for (int i = 0; i < n; i++) {
+                arr[i] = scanner.nextInt();
+            }
+
+            System.out.println("Original array: " + Arrays.toString(arr));
+
+            radixSort(arr);
+
+            System.out.println("Sorted array: " + Arrays.toString(arr));
+        } catch (InputMismatchException e) {
+            System.out.println("Invalid input. Please enter integers only.");
+        } catch (IllegalArgumentException e) {
+            System.out.println(e.getMessage());
+        } finally {
+            scanner.close();
+        }
+    }
+}