experimental feature, algorithm/sorter.go try to implements sort function with go generics

algorithm/sorter.go

@@ -0,0 +1,53 @@
+// Copyright 2021 dudaodong@gmail.com. All rights reserved.
+// Use of this source code is governed by MIT license
+
+// Package algorithm contain some algorithm functions. eg. sort, find, list, linklist, stack, queue, tree, graph. TODO
+package algorithm
+
+import "github.com/duke-git/lancet/lancetconstraints"
+
+// SelectionSort use selection to sort slice,
+func SelectionSort[T any](slice []T, comparator lancetconstraints.Comparator) []T {
+	for i := 0; i < len(slice); i++ {
+		min := i
+
+		for j := i + 1; j < len(slice); j++ {
+			if comparator.Compare(slice[j], slice[min]) == -1 {
+				min = j
+			}
+		}
+		swap(slice, i, min)
+	}
+	return slice
+}
+
+// func QuickSort[T comparable](slice []T, low, high int) []T {
+// 	if low < high {
+// 		var p int
+// 		slice, p = partitionForQuickSort(slice, low, high)
+// 		slice = quickSort(slice, low, p-1)
+// 		slice = quickSort(slice, p+1, high)
+// 	}
+
+// 	return slice
+// }
+
+// swap two slice value at index i and j
+func swap[T any](slice []T, i, j int) {
+	slice[i], slice[j] = slice[j], slice[i]
+}
+
+// func partition[T comparable](slice []T, low, high int) ([]T, int) {
+// 	p := slice[high]
+// 	i := low
+// 	for j := low; j < high; j++ {
+// 		//???, error: comparable don't support operator <
+// 		if slice[j] < p {
+// 			slice[i], slice[j] = slice[j], slice[i]
+// 			i++
+// 		}
+// 	}
+// 	slice[i], slice[high] = slice[high], slice[i]
+
+// 	return slice, i
+// }

algorithm/sorter_test.go

@@ -0,0 +1,58 @@
+package algorithm
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/duke-git/lancet/internal"
+)
+
+// People test mock data
+type People struct {
+	Name string
+	Age  int
+}
+
+// PeopleAageComparator sort people slice by age field
+type PeopleAageComparator struct{}
+
+// Compare implements github.com/duke-git/lancet/lancetconstraints/constraints.go/Comparator
+func (pc *PeopleAageComparator) Compare(v1 interface{}, v2 interface{}) int {
+	p1, _ := v1.(People)
+	p2, _ := v2.(People)
+
+	//ascending order
+	if p1.Age < p2.Age {
+		return -1
+	} else if p1.Age > p2.Age {
+		return 1
+	}
+	return 0
+
+	//decending order
+	// if p1.Age > p2.Age {
+	// 	return -1
+	// } else if p1.Age < p2.Age {
+	// 	return 1
+	// }
+}
+
+var peoples = []People{
+	{Name: "a", Age: 20},
+	{Name: "b", Age: 10},
+	{Name: "c", Age: 17},
+	{Name: "d", Age: 8},
+	{Name: "e", Age: 28},
+}
+
+func TestSelectionSort(t *testing.T) {
+	asssert := internal.NewAssert(t, "TestSelectionSort")
+	comparator := &PeopleAageComparator{}
+	sortedPeopleByAge := SelectionSort(peoples, comparator)
+	t.Log(sortedPeopleByAge)
+
+	expected := "[{d 8} {b 10} {c 17} {a 20} {e 28}]"
+	actual := fmt.Sprintf("%v", sortedPeopleByAge)
+
+	asssert.Equal(expected, actual)
+}