feat: add bucket sort

Author: codejsha

README.md

@@ -1172,7 +1172,7 @@ list.sort(Comparator.comparingInt(String::length));
 | **Worst**   |      $O(n^2)$       | when the input list is already sorted in the reverse order of the desired sorting order |
 | **Average** |      $O(n^2)$       | when the input list is in jumbled order                                                 |
 
-- Bucket sort, CLRS#8.4: [java](/java-algorithm/src/main/java/com/example/algorithm/sort/BucketSort.java) | Bucket sort is a sorting algorithm that works by distributing the elements of an array into a number of buckets. Each bucket contains a range of values and the elements are sorted within these buckets using any of the suitable sorting algorithms (such as insertion sort, merge sort, selection sort).<br>($\textit{n}$ is the number of elements and $\textit{k}$ is the number of buckets)
+- Bucket sort, CLRS#8.4: [golang](go-algorithm/pkg/sort/bucket_sort.go), [java](/java-algorithm/src/main/java/com/example/algorithm/sort/BucketSort.java) | Bucket sort is a sorting algorithm that works by distributing the elements of an array into a number of buckets. Each bucket contains a range of values and the elements are sorted within these buckets using any of the suitable sorting algorithms (such as insertion sort, merge sort, selection sort).<br>($\textit{n}$ is the number of elements and $\textit{k}$ is the number of buckets)
 
 | **Case**    | **Time complexity** | **Remarks**                                                                                                    |
 | ----------- | :-----------------: | -------------------------------------------------------------------------------------------------------------- |

go-algorithm/pkg/sort/bucket_sort.go

@@ -0,0 +1,46 @@
+package sort
+
+import (
+	"math"
+
+	"golang.org/x/exp/constraints"
+)
+
+func bucketSort[T constraints.Integer](arr []T) []T {
+	n := len(arr)
+
+	var maxVal, minVal T
+	for _, v := range arr {
+		if v > maxVal {
+			maxVal = v
+		}
+		if v < minVal {
+			minVal = v
+		}
+	}
+	rangeVal := maxVal - minVal
+
+	bucket := make([][]T, n)
+	for i := 0; i < n; i++ {
+		bucket[i] = make([]T, 0)
+	}
+
+	for _, v := range arr {
+		index := int(math.Floor(float64(n) * float64((v-minVal)/rangeVal)))
+		if index == n {
+			index--
+		}
+		bucket[index] = append(bucket[index], v)
+	}
+
+	for i := 0; i < n; i++ {
+		insertionSort(bucket[i])
+	}
+
+	sorted := make([]T, 0, n)
+	for i := 0; i < n; i++ {
+		sorted = append(sorted, bucket[i]...)
+	}
+
+	return sorted
+}

go-algorithm/pkg/sort/bucket_sort_test.go

@@ -0,0 +1,41 @@
+package sort
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_bucketSortInteger(t *testing.T) {
+	type args struct {
+		arr []int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []int
+	}{
+		{
+			name: "Integer Case",
+			args: args{
+				arr: []int{31, 64, 49, 85, 71, 26, 6, 19},
+			},
+			want: []int{6, 19, 26, 31, 49, 64, 71, 85},
+		},
+		{
+			name: "Empty array input",
+			args: args{
+				arr: []int{},
+			},
+			want: []int{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := bucketSort(tt.args.arr)
+
+			assert.Equalf(t, tt.want, got, "bucketSort() got = %v, want %v", got, tt.want)
+		})
+	}
+}