增加选择排序

Author: xiaomeng79

bubble/bubble_test.go

@@ -3,29 +3,19 @@ package bubble
 import (
 	"github.com/stretchr/testify/assert"
 	"testing"
+	"github.com/xiaomeng79/go-algorithm/testdata"
 )
 
-var (
-	values = []struct {
-		nosort []int
-		sort   []int
-	}{
-		{[]int{3, 44, 56, 38, 77, 38, 26}, []int{3, 26, 38, 38, 44, 56, 77}},
-		{[]int{3}, []int{3}},
-		{[]int{3, -1, -6, 34, -78}, []int{-78, -6, -1, 3, 34}},
-	}
-	value = []int{3, 44, 56, 38, 77, 38, 26}
-)
 
 func TestBubbleSort(t *testing.T) {
-	for _, v := range values {
-		assert.Exactly(t, v.sort, BubbleSort(v.nosort), "no eq")
+	for _, v := range testdata.Values {
+		assert.Exactly(t, v.Sort, BubbleSort(v.Nosort), "no eq")
 	}
 }
 
 func BenchmarkBubbleSort(b *testing.B) {
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
-		BubbleSort(value)
+		BubbleSort(testdata.Value)
 	}
 }

insertion/insertion.go

@@ -2,7 +2,7 @@
 package insertion
 
 //原理：通过构建有序序列，对于未排序数据，在已排序序列中从后向前扫描，找到相应位置并插入
-
+//稳定性：稳定
 //算法步骤:
 // 1.第一待排序序列第一个元素看做一个有序序列，把第二个元素到最后一个元素当成是未排序序列
 // 2.从头到尾依次扫描未排序序列，将扫描到的每个元素插入有序序列的适当位置。（如果待插入的元素与有序序列中的某个元素相等，则将待插入元素插入到相等元素的后面

insertion/insertion_test.go

@@ -3,29 +3,19 @@ package insertion
 import (
 	"github.com/stretchr/testify/assert"
 	"testing"
+	"github.com/xiaomeng79/go-algorithm/testdata"
 )
 
-var (
-	values = []struct {
-		nosort []int
-		sort   []int
-	}{
-		{[]int{3, 44, 56, 38, 77, 38, 26}, []int{3, 26, 38, 38, 44, 56, 77}},
-		{[]int{3}, []int{3}},
-		{[]int{3, -1, -6, 34, -78}, []int{-78, -6, -1, 3, 34}},
-	}
-	value = []int{3, 44, 56, 38, 77, 38, 26}
-)
 
 func TestInsertionSort(t *testing.T) {
-	for _, v := range values {
-		assert.Exactly(t, v.sort, InsertionSort(v.nosort), "no eq")
+	for _, v := range testdata.Values {
+		assert.Exactly(t, v.Sort, InsertionSort(v.Nosort), "no eq")
 	}
 }
 
 func BenchmarkInsertionSort(b *testing.B) {
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
-		InsertionSort(value)
+		InsertionSort(testdata.Value)
 	}
 }

selection/selection.go

@@ -0,0 +1,28 @@
+//选择排序
+package selection
+
+//原理：每一次从待排序的数据元素中选出最小（或最大）的一个元素，存放在序列的起始位置
+//稳定: 不稳定
+//适用: 数据规模越小越好
+//算法步骤:
+//1. 首先在未排序序列中找到最小（大）元素，存放到排序序列的起始位置
+//2. 再从剩余未排序元素中继续寻找最小（大）元素，然后放到已排序序列的末尾
+//3. 重复第二步，直到所有元素均排序完毕
+
+func SelectionSort(arr []int) []int {
+	length := len(arr)
+	for i:= 0;i < length-1;i++ {//注意这里使用length-1少一次，
+		minIndex := i
+		for j:= i+1;j<length;j++ {
+			if arr[j] < arr[minIndex] {
+				minIndex = j
+			}
+		}
+		//
+		arr[minIndex],arr[i] = arr[i],arr[minIndex]
+	}
+	return arr
+}
+
+
+

selection/selection_test.go

@@ -0,0 +1,22 @@
+package selection
+
+import (
+	"testing"
+	"github.com/stretchr/testify/assert"
+	"github.com/xiaomeng79/go-algorithm/testdata"
+)
+
+func TestSelectionSort(t *testing.T) {
+	for _, v := range testdata.Values {
+		assert.Exactly(t, v.Sort, SelectionSort(v.Nosort), "no eq")
+	}
+}
+
+
+func BenchmarkSelectionSort(b *testing.B) {
+	b.ReportAllocs()
+	for i:=0;i<b.N;i++ {
+		SelectionSort(testdata.Value)
+	}
+}
+

testdata/sortdata.go

@@ -0,0 +1,13 @@
+package testdata
+
+var (
+	Values = []struct {
+		Nosort []int
+		Sort   []int
+	}{
+		{[]int{3, 44, 56, 38, 77, 38, 26}, []int{3, 26, 38, 38, 44, 56, 77}},
+		{[]int{3}, []int{3}},
+		{[]int{3, -1, -6, 34, -78}, []int{-78, -6, -1, 3, 34}},
+	}
+	Value = []int{3, 44, 56, 38, 77, 38, 26}
+)