Bucket Sort

Distribute the array into a finite number of buckets. Perform sorting on each bucket individually, and then concatenate the sorted buckets to obtain the final result.
::: code-tabs
@tab Java

public class BucketSort implements IArraySort {
    private static final InsertSort insertSort = new InsertSort();
    @Override
    public int[] sort(int[] sourceArray) throws Exception {
        // Create a copy of arr to avoid modifying the original parameter content
        int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
        return bucketSort(arr, 5);
    }
    private int[] bucketSort(int[] arr, int bucketSize) throws Exception {
        if (arr.length == 0) {
            return arr;
        }
        int minValue = arr[0];
        int maxValue = arr[0];
        for (int value : arr) {
            if (value < minValue) {
                minValue = value;
            } else if (value > maxValue) {
                maxValue = value;
            }
        }
        int bucketCount = (int) Math.floor((maxValue - minValue) / bucketSize) + 1;
        int[][] buckets = new int[bucketCount][0];
        // Distribute data into various buckets using a mapping function
        for (int i = 0; i < arr.length; i++) {
            int index = (int) Math.floor((arr[i] - minValue) / bucketSize);
            buckets[index] = arrAppend(buckets[index], arr[i]);
        }
        int arrIndex = 0;
        for (int[] bucket : buckets) {
            if (bucket.length <= 0) {
                continue;
            }
            // Sort each bucket; Insertion Sort is used here
            bucket = insertSort.sort(bucket);
            for (int value : bucket) {
                arr[arrIndex++] = value;
            }
        }
        return arr;
    }
    /**
     * Automatically expand capacity and save data
     */
    private int[] arrAppend(int[] arr, int value) {
        arr = Arrays.copyOf(arr, arr.length + 1);
        arr[arr.length - 1] = value;
        return arr;
    }
}

@tab JavaScript

function bucketSort(arr, bucketSize) {
    if (arr.length === 0) {
      return arr;
    }
    var i;
    var minValue = arr[0];
    var maxValue = arr[0];
    for (i = 1; i < arr.length; i++) {
      if (arr[i] < minValue) {
          minValue = arr[i];                // The minimum value of the input data
      } else if (arr[i] > maxValue) {
          maxValue = arr[i];                // The maximum value of the input data
      }
    }
    // Initialize buckets
    var DEFAULT_BUCKET_SIZE = 5;            // Set the default number of buckets to 5
    bucketSize = bucketSize || DEFAULT_BUCKET_SIZE;
    var bucketCount = Math.floor((maxValue - minValue) / bucketSize) + 1;   
    var buckets = new Array(bucketCount);
    for (i = 0; i < buckets.length; i++) {
        buckets[i] = [];
    }
    // Distribute data into various buckets using a mapping function
    for (i = 0; i < arr.length; i++) {
        buckets[Math.floor((arr[i] - minValue) / bucketSize)].push(arr[i]);
    }
    arr.length = 0;
    for (i = 0; i < buckets.length; i++) {
        insertionSort(buckets[i]);                      // Sort each bucket; Insertion Sort is used here
        for (var j = 0; j < buckets[i].length; j++) {
            arr.push(buckets[i][j]);                      
        }
    }
    return arr;
}

@tab PHP

function bucketSort($arr, $bucketSize = 5)
{
    if (count($arr) === 0) {
      return $arr;
    }
    $minValue = $arr[0];
    $maxValue = $arr[0];
    for ($i = 1; $i < count($arr); $i++) {
      if ($arr[$i] < $minValue) {
          $minValue = $arr[$i];
      } else if ($arr[$i] > $maxValue) {
          $maxValue = $arr[$i];
      }
    }
    $bucketCount = floor(($maxValue - $minValue) / $bucketSize) + 1;
    $buckets = array();
    for ($i = 0; $i < count($buckets); $i++) {
        $buckets[$i] = [];
    }
    for ($i = 0; $i < count($arr); $i++) {
        $buckets[floor(($arr[$i] - $minValue) / $bucketSize)][] = $arr[$i];
    }
    $arr = array();
    for ($i = 0; $i < count($buckets); $i++) {
        $bucketTmp = $buckets[$i];
        sort($bucketTmp);
        for ($j = 0; $j < count($bucketTmp); $j++) {
            $arr[] = $bucketTmp[$j];
        }
    }
    return $arr;
}

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