BucketSort.java

// Bucket sort in Java

import java.util.ArrayList;

import java.util.Collections;

public class BucketSort {

  public void bucketSort(float[] arr, int n) {

    if (n <= 0)

      return;

    @SuppressWarnings("unchecked")

    ArrayList<Float>[] bucket = new ArrayList[n];

    // Create empty buckets

    for (int i = 0; i < n; i++)

      bucket[i] = new ArrayList<Float>();

    // Add elements into the buckets

    for (int i = 0; i < n; i++) {

      int bucketIndex = (int) arr[i] * n;

      bucket[bucketIndex].add(arr[i]);

    }

    // Sort the elements of each bucket

    for (int i = 0; i < n; i++) {

      Collections.sort((bucket[i]));

    }

    // Get the sorted array

    int index = 0;

    for (int i = 0; i < n; i++) {

      for (int j = 0, size = bucket[i].size(); j < size; j++) {

        arr[index++] = bucket[i].get(j);

      }

    }

  }

  // Driver code

  public static void main(String[] args) {

    BucketSort b = new BucketSort();

    float[] arr = { (float) 0.42, (float) 0.32, (float) 0.33, (float) 0.52, (float) 0.37, (float) 0.47,

        (float) 0.51 };

    b.bucketSort(arr, 7);

    for (float i : arr)

      System.out.print(i + "  ");

  }

}