基础算法之排序算法

排序算法的Golang实现

package main

import (
	"fmt"
)
//冒泡排序：升序
func BubbleSort(s []int)  {
	for i:= 0;i < len(s);i++{
		for j := 0;j < len(s) - 1 - i;j++{
			if s[j] > s[j+1] {
				temp := s[j]
				s[j] = s[j+1]
				s[j+1] = temp
			}
		}
	}
}

//选择排序:升序
func SelectSort(nums []int)  {
	for i := 0;i < len(nums);i++{
		min := nums[i]
		minIndex := i
		for j := i + 1;j < len(nums);j++{
			if min > nums[j] {
				min = nums[j]
				minIndex = j
			}
		}
		nums[minIndex] = nums[i]
		nums[i] = min
	}
}

//快速排序
func QuickSort(s []int,left,right int)  {
	sort := func(s []int,low,high int)int {
		tmp := s[low]
		for low < high{
			for low < high && s[high] >= tmp{
				high--
			}
			s[low],s[high] = s[high],s[low]
			for low < high && s[low] <= tmp{
				low++
			}
			s[low],s[high] = s[high],s[low]
		}
		return low
	}
	if left < right {
		index := sort(s,left,right)
		QuickSort(s,left,index-1)
		QuickSort(s,index+1,right)
	}
}

//堆排序
func heapSort(s []int)  {
	heapAdjust := func(s []int,parent,len int) {
		var i int
		for 2 * parent + 1 < len{
			lchild := 2 * parent + 1
			rchild := lchild + 1
			i = lchild
			//取出两个子节点中最大的一个
			if rchild < len && s[rchild] > s[lchild]{
				i = rchild
			}
			//如果最大节点大于父节点则交换，否则退出循环
			if s[i] > s[parent] {
				s[parent],s[i] = s[i],s[parent]
				parent = i
			}else {
				break
			}
		}
	}
	//从最后一个非叶子节点开始调整（len(s)/2 - 1）
	for i := len(s)/2 - 1;i >= 0;i--{
		heapAdjust(s,i,len(s))
	}
	for i := len(s) - 1;i > 0;i--{
		s[0],s[i] = s[i],s[0]
		heapAdjust(s,0,i)
	}
}

//归并排序
func merge(left,right []int) []int  {
	result := make([]int,0)
	m,n := 0,0
	l,r := len(left),len(right)
	for m < l && n < r {
		if left[m] > right[n] {
			result = append(result,right[n])
			n++
			continue
		}
		result = append(result,left[m])
		m++
	}
	result = append(result,right[n:]...)
	result = append(result,left[m:]...)
	return result
}

func mergeSort(arr []int) []int {
	if len(arr) < 2 {
		return arr
	}
	i := len(arr)/2
	left := mergeSort(arr[0:i])
	right := mergeSort(arr[i:])
	result := merge(left,right)
	return result
}

func main() {
	//数组是属于值类型，方法传递的话应该是副本
	array := []int{9,20,1,3,2,80,76}
	//BubbleSort(array)
	//SelectSort(array)
	//QuickSort(array,0,len(array) - 1)
	//堆排序
	//heapSort(array)
	//归并排序
	array = mergeSort(array)
	fmt.Println(array)
}