最近有时间，都在看Go，感觉Go语言真的不错，具体自行百度。今天简单说一下算法
- 什么是算法
一系列的计算步骤，用来将输入数据转化成输出结果 - 算法的意义
用于解决特定的问题
解决同一个问题的不同算法的效率常常相差非常大，这种差距的影响往往比硬件和软件方面的差距还要大。
算法在我们编程开发中，还是不可或缺的。
下面简单来列举一下go语言常见的十大算法。具体如下:
- BubbleSort(冒泡排序)
func Sort(list []int, left, right int) {
if right == 0 {
return
}
for index,num := range list {
if index < right && num > list[index + 1] {
utils.SwapGo(list, index, index + 1)
}
}
Sort(list, left, right - 1)
}
- BucketSort(桶排序)
func Sort(list []int) []int{
max := max(list)
min := min(list)
base := 0
if min < 0 {
base = -min
} else {
base = min
}
max = (max + base)/10
min = (min + base)/10
bucket := make([][]int, max - min + 1)
var result []int
for _,value := range list {
i := (int)((value+base)/10)
bucket[i] = append(bucket[i], value)
}
for _,value := range bucket {
if len(value) > 0 {
quicksort.Sort(value, 0, len(value)-1)
}
}
for _,value := range bucket {
if len(value) > 0 {
for _,v := range value {
result = append(result,v)
}
}
}
return result
}
func max(list []int) int {
max := list[0]
for _,value := range list {
if value > max {
max = value
}
}
return max
}
func min(list []int) int {
min := list[0]
for _,value := range list {
if value < min {
min = value
}
}
return min
}
- CountSort (计数排序)
func Sort(list []int) []int{
max := max(list)
min := min(list)
base := -min
max = max - base
min = min - base
numbers := make([]int, max - min + 1)
for _,value := range list{
numbers[value + base] = numbers[value + base] + 1
}
var result []int
for i,value := range numbers {
for j:=value;j>0 && value > 0;j-- {
result = append(result, i - base)
}
}
return result
}
func max(list []int) int {
max := list[0]
for _,value := range list {
if value > max {
max = value
}
}
return max
}
func min(list []int) int {
min := list[0]
for _,value := range list {
if value < min {
min = value
}
}
return min
}
- HeapSort(堆排序)
func Sort(list []int) {
length := len(list)
for {
if length < 1 {
break
}
index := length/2 -1
for ;index>=0;index-- {
swap(list, index, length-1)
}
tmp := list[0]
list[0] = list[length - 1]
list[length - 1] = tmp
length--
}
}
func swap(list []int, index int, length int) {
left := 2*index + 1
right := 2*index + 2
if left <= length && list[left] > list[index] {
tmp := list[index]
list[index] = list[left]
list[left] = tmp
}
if right <= length && list[right] > list[index] {
tmp := list[index]
list[index] = list[right]
list[right] = tmp
}
}
- InsertSort(插入排序)
func Sort(list []int, left, right int) {
for index := left;index <= right;index++ {
if index > 0 {
for i:=index;i>0;i-- {
current := list[i]
pre := list[i-1]
if current <= pre {
utils.SwapGo(list, i, i-1)
} else {
break
}
}
}
}
}
- MergeSort(合并排序)
func Sort(list []int, left, right int) []int{
return mergeSort(list[left:right-left + 1])
}
func mergeSort(list []int) []int {
if len(list) < 2 {
return list
} else {
return merge(mergeSort(list[:len(list)/2]), mergeSort(list[len(list)/2:]))
}
}
func merge(list0, list1 []int) []int{
var result []int
index0 := 0
index1 := 0
for {
if index0 < len(list0) && index1 < len(list1) {
if list0[index0] < list1[index1] {
result = append(result, list0[index0])
index0 = index0 + 1
} else {
result = append(result, list1[index1])
index1 = index1 + 1
}
} else {
break
}
}
if index0 < len(list0) {
result = append(result, list0[index0:]...)
}
if index1 < len(list1) {
result = append(result, list1[index1:]...)
}
return result
}
- QuickSort(快速排序)
import "github.com/go-algorithm/utils"
func Sort(list []int, left, right int) {
if right < left {
return
}
flag := list[left]
start := left
end := right
for {
if start == end {
break
}
for list[end] >= flag && end > start {
end--
}
for list[start] <= flag && end > start {
start++
}
if end > start {
utils.SwapGo(list, start, end)
}
}
utils.SwapGo(list, left, start)
Sort(list, left, start - 1)
Sort(list, start + 1, right)
}
- RadixSort(基数排序)
func Sort(list []int) {
baseList := make([][]int, 10)
maxDigist := maxDigist(list)
for i:=0;i<maxDigist;i++ {
for _,value := range list {
baseList[getDigist(value, i)] = append(baseList[getDigist(value, i)], value)
}
j := 0
for index,value :=range baseList {
if len(value) > 0 {
for _,v := range value {
list[j] = v
j++
}
}
baseList[index] = nil
}
}
}
func maxDigist(list []int) int {
maxDigist := 1
for _,value := range list {
if len(strconv.Itoa(value)) > maxDigist {
maxDigist = len(strconv.Itoa(value))
}
}
return maxDigist
}
func getDigist(number int, index int) int {
strNum := strconv.Itoa(number)
if index > len(strNum) - 1 {
return 0
}
index = len(strNum) - 1 - index
//fmt.Println("index = ", index)
result,error := strconv.Atoi(string(strNum[index]))
if error != nil {
return -1
} else {
return result
}
}
- SelectSort(选择排序)
import "github.com/go-algorithm/utils"
func Sort(list []int, left, right int) {
if left == right {
return
}
minIndex := left
for i:=left;i<=right;i++ {
if list[i] <= list[minIndex] {
minIndex = i
}
}
utils.SwapGo(list, left, minIndex)
Sort(list, left + 1, right)
}
- shellsort(希尔排序)
func Sort(list []int, left, right int) {
increment := len(list)/3 + 1
for {
if increment < 1 {
break
}
for i:=left;i<increment;i++ {
for j:=i+increment;j<=right;j++ {
if list[j] < list[j-increment] {
tmp := list[j]
list[j] = list[j-increment]
list[j-increment] = tmp
}
}
}
increment--
}
}
附：Utils.go
/***
* 变量交换
*/
func Swap(list []int, i, j int) {
tmp := list[i]
list[i] = list[j]
list[j] = tmp
}
/***
* go特有变量交换
*/
func SwapGo(list []int, i, j int) {
list[i],list[j]=list[j],list[i]
}
/***
* go变量高阶交换(不推荐，一般不好理解)
*/
func SwapGoAdvanced(list []int, i, j int) {
list[i]=list[i]+list[j]
list[j]=list[i]-list[j]
list[i]=list[i]-list[j]
}
运行排序方法
- 使用终端执行
go get github.com/e9ab98e991ab/go-algorithm - 执行
touch main.go - 执行
vim main.go - 拷贝下方代码块代码到
main.go文件中 - wq保存后直接执行
go run main.go即可查看结果
package main
import (
"fmt"
"github.com/e9ab98e991ab/go-algorithm/bubblesort"
"github.com/e9ab98e991ab/go-algorithm/quicksort"
"github.com/e9ab98e991ab/go-algorithm/selectsort"
"github.com/e9ab98e991ab/go-algorithm/insertsort"
"github.com/e9ab98e991ab/go-algorithm/shellsort"
"github.com/e9ab98e991ab/go-algorithm/radixsort"
"github.com/e9ab98e991ab/go-algorithm/heapsort"
"github.com/e9ab98e991ab/go-algorithm/bucketsort"
"github.com/e9ab98e991ab/go-algorithm/countsort"
"github.com/e9ab98e991ab/go-algorithm/mergesort"
)
var data = []int{8, 3, 6, 9, 11, 2, 7, 23, 65, 13, 9}
func main() {
datePrintln("桶排序")
datePrintln("计数排序")
datePrintln("冒泡排序")
datePrintln("快速排序")
datePrintln("选择排序")
datePrintln("插入排序")
datePrintln("希尔排序")
datePrintln("合并排序")
datePrintln("基数排序")
datePrintln("堆排序")
}
func datePrintln(name string) {
var result []int
fmt.Println("初始数据:", data)
switch name {
case "桶排序":
result = bucketsort.Sort(data)
break
case "计数排序":
result = countsort.Sort(data)
break
case "合并排序":
result = mergesort.Sort(data, 0, len(data)-1)
break
case "冒泡排序":
bubblesort.Sort(data, 0, len(data)-1)
result = data
break
case "快速排序":
quicksort.Sort(data, 0, len(data)-1)
result = data
break
case "选择排序":
selectsort.Sort(data, 0, len(data)-1)
result = data
break
case "插入排序":
insertsort.Sort(data, 0, len(data)-1)
result = data
break
case "希尔排序":
shellsort.Sort(data, 0, len(data)-1)
result = data
break
case "基数排序":
radixsort.Sort(data)
result = data
break
case "堆排序":
heapsort.Sort(data)
result = data
break
}
fmt.Println(name+":", result)
data = []int{8, 3, 6, 9, 11, 2, 7, 23, 65, 13, 9}
fmt.Println("原始数据:", data, "\n")
}
源码地址：GitHub
