go实现冒泡排序和快速排序

Posted 2020-10-20 Yxh_blogs

项目结构

冒泡排序算法，源文件bubblesort.go

package bubblesort

// 冒泡排序
func BubbleSort(values []int)  {
	for i := 0; i < len(values) - 1; i ++ {
		flag := true
		for j := 0; j < len(values) - i - 1; i ++ {
			if values[j] > values[j + 1] {
				values[j], values[j + 1] = values[j + 1], values[j]
				flag = false
			}

			if flag == true {
				break
			}
		}
	}
}

快速排序算法，源文件qsort.go

package qsort

// 快速排序
func quickSort(values []int, left, right int)  {
	temp := values[left] //第一个值
	p := left //第一个位置
	i, j := left, right //第一个位置和最后一个位置
	for i <= j {
		for j >= p && values[j] >= temp {
			j--
		}
		if j >= p {
			values[p] = values[j]
			p = j
		}
		if values[i] <= temp && i <= p {
			i++
		}
		if i <= p {
			values[p] = values[i]
			p = i
		}
	}
	values[p] = temp
	if p - left > 1 {
		quickSort(values, left, p - 1) //递归调用
	}
	if right - p > 1 {
		quickSort(values, p + 1, right) //递归调用
	}
}

func QuickSort(values []int)  {
	quickSort(values, 0 , len(values) - 1)
}

主文件main.go

package main

import (
	"flag"
	"os"
	"bufio"
	"io"
	"strconv"
	"time"
	"sorter/algorithms/qsort"
	"sorter/algorithms/bubblesort"
	"fmt"
)

var infile *string = flag.String("i","unsorted.dat","File  contains values of sorting")
var outfile *string = flag.String("o","sorted.dat","File to receive sorted values")
var algorithm *string = flag.String("a","qsort","Sort algorithm")

// 从文件读取值
func readValues(infile string) (values []int, err error){
	file, err := os.Open(infile)
	if err != nil {
		println("Failed to open the input file ", infile)
		return
	}
	defer file.Close()
	br := bufio.NewReader(file)
	values = make([]int, 0)
	for {
		line, isPrefix, err1 := br.ReadLine()
		if err1 != nil {
			if err1 != io.EOF {
				err = err1
			}
			break
		}
		if isPrefix {
			println("A too long line, seems unexpected.")
			return
		}
		str := string(line)//转换字符数组为字符串
		value, err1 := strconv.Atoi(str)
		if err1 != nil {
			err = err1
			return
		}
		values = append(values, value)
	}
	return
}

// 将值写入到文件中
func writeValues(values []int, outfile string) error {
	file, err := os.Create(outfile)
	if err != nil {
		println("Failed to create the ouput file ", outfile)
		return err
	}
	defer file.Close()

	for _, value := range values {
		str := strconv.Itoa(value)
		file.WriteString(str + "\\n")
	}
	return nil
}

func main()  {
	flag.Parse()
	if infile != nil {
		println("infile =", *infile,"outfile=", *outfile, "algorithm =", *algorithm)
	}
	values, err := readValues(*infile)
	if err == nil {
		fmt.Println("Read values:%v", values)
		if err == nil {
			t1 := time.Now()
			switch *algorithm {
			case "qsort":
				qsort.QuickSort(values)
			case "bubblesort":
				bubblesort.BubbleSort(values)
			default:
				println("Sorting algorithm", *algorithm, "is either unknown or unsupported.")
			}
			t2 := time.Now()
			println("The sorting process conts", t2.Sub(t1), "to complete.")

			writeValues(values, *outfile)
		}
	}else{
		println(err)
	}
}

排序结果