Radix

algorithms/radix.go

@@ -0,0 +1,27 @@
+package algorithms
+
+func RadixSort(arr []int) []int {
+	n := len(arr)
+	result := make([]int, n)
+	copy(result, arr)
+
+	var partitions [10][]int
+	for i := range partitions {
+		partitions[i] = make([]int, 0)
+	}
+	divider := 10
+	for {
+		if len(partitions[0]) == n {
+			return partitions[0]
+		}
+		for i := 0; i < n; i++ {
+			partition := (result[i] / (divider / 10)) % divider
+			partitions[partition] = append(partitions[partition], result[i])
+		}
+		result = make([]int, 0)
+		for i := 0; i < 10; i++ {
+			result = append(result, partitions[i]...)
+		}
+		divider = divider * 10
+	}
+}

algorithms_test/radix_test.go

@@ -0,0 +1,33 @@
+package algorithms_test
+
+import (
+	"github.com/dimitrijjedich/go-algorithms/algorithms"
+	"reflect"
+	"testing"
+)
+
+func TestRadixSort(t *testing.T) {
+	testCases := []struct {
+		name     string
+		input    []int
+		expected []int
+	}{
+		{"already sorted", []int{1, 2, 3, 4, 5}, []int{1, 2, 3, 4, 5}},
+		{"reverse sorted", []int{5, 4, 3, 2, 1}, []int{1, 2, 3, 4, 5}},
+		{"unsorted array", []int{5, 3, 8, 6, 2}, []int{2, 3, 5, 6, 8}},
+		{"non consecutive array", []int{9, 3, 5, 1, 7}, []int{1, 3, 5, 7, 9}},
+		{"empty array", []int{}, []int{}},
+		{"single element", []int{42}, []int{42}},
+		{"duplicates", []int{3, 1, 2, 3, 1}, []int{1, 1, 2, 3, 3}},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			result := algorithms.RadixSort(testCase.input)
+
+			if !reflect.DeepEqual(result, testCase.expected) {
+				t.Errorf("Failed %s: expected %v, got %v", testCase.name, testCase.expected, result)
+			}
+		})
+	}
+}