github.com/benz9527/toy-box/algo@v0.0.0-20240221120937-66c0c6bd5abd/sort/bucket.go (about)

     1  package sort
     2  
     3  /*
     4  The process of bucket sort can be understood as scatter-gather approach.
     5  Here, elements are first scattered into buckets then the elements in each buckets are sorted.
     6  Finally, the elements are gathered in order.
     7  
     8  1.创建固定数量的 buckets
     9  2.bucket size 最好通过归一化的处理后平均划分（也不是绝对均分），大于 0 小于 1 的 float 可以通过扩大相同倍数（> 1 整数）
    10  来进行 size 划分
    11  */
    12  
    13  func BucketSort(arr []int) {
    14  	n := len(arr)
    15  	BUCKET_SIZE := 10
    16  	buckets := make([][]int, BUCKET_SIZE)
    17  	max := getMax(arr, n)
    18  	var interval int = max / BUCKET_SIZE
    19  	if max%BUCKET_SIZE > 0 {
    20  		interval++
    21  	}
    22  
    23  	for i := 0; i < n; i++ {
    24  		bucketIdx := arr[i]/interval - 1
    25  		if arr[i]%interval > 0 {
    26  			bucketIdx++
    27  		} else if bucketIdx == -1 {
    28  			bucketIdx = 0
    29  		}
    30  
    31  		buckets[bucketIdx] = append(buckets[bucketIdx], arr[i])
    32  	}
    33  
    34  	origIdx := 0
    35  	for i := 0; i < BUCKET_SIZE && origIdx < n; i++ {
    36  		blen := len(buckets[i])
    37  		if blen > 0 {
    38  			InsertSortSimplify(buckets[i])
    39  
    40  			for j := 0; j < blen; j++ {
    41  				arr[origIdx] = buckets[i][j]
    42  				origIdx++
    43  			}
    44  		}
    45  	}
    46  }