基於空介面的go語言快速排序quickSort

//快速排序，空介面//1 取參考點pivot: arr[low] arr[mid] arr[high]的中位元//2 將pivot放置合適位置//3 二分排序//4 待排序元素個數低於4個普通排序演算法//5 go語言可以直接交換，不需要swappackage mySort1import (    "fmt"    "log")func median3(arr []interface{}, low, high int) (pivot interface{}) {    //var pivot int    mid := (low + high) / 2    //arr[low]放置三者最小值    if !compare(arr[low], arr[mid]) {        arr[low], arr[mid] = arr[mid], arr[low]    }    if !compare(arr[low], arr[high]) {        arr[low], arr[high] = arr[high], arr[low]    }    //arr[high]放置三者最大者    if !compare(arr[mid], arr[high]) {        arr[mid], arr[high] = arr[high], arr[mid]    }    pivot = arr[mid]    //交換arr[high-1]為arr[mid]值    arr[mid], arr[high-1] = arr[high-1], arr[mid]    //返回參考值pivot    return pivot}//QuickSort在mySort1包中func QuickSort(arr []interface{}, low, high int) {    if low > high || high > (len(arr)-1) {        log.Panicln("input error: low > high")    }    if (low + 3) <= high {        pivot := median3(arr, low, high)        //fmt.Println("pivot: ", pivot)        //fmt.Println("pivot arr: ", arr)        i, j := low+1, (high - 2)        for {            //左側            for {                if compare(arr[i], pivot) {                    i++                } else {                    break                }            }            //fmt.Println("arr[i]: ", arr[i])            //右側            for {                if !compare(arr[j], pivot) {                    j--                } else {                    break                }            }            //fmt.Println("arr[j]: ", arr[j])            //將大數交換至pivot右側            //將小數交換至pivot左側            if i < j {                arr[i], arr[j] = arr[j], arr[i]            } else {                break //pivot找到合適位置            }        }        //pivot放置合適位置        arr[i], arr[high-1] = arr[high-1], arr[i]        //fmt.Println("arr: ", arr)        //分        QuickSort(arr, low, i-1)        QuickSort(arr, i+1, high)    } else {        //待排序元素個數低於4個,simpleSort函數處理        simpleSort(arr, low, high)    }}func simpleSort(arr []interface{}, low, high int) {    if (high - low + 1) < 1 {        fmt.Println("arr is empty")    }    if (high - low + 1) == 1 {    }    if (high - low + 1) == 2 {        if !compare(arr[low], arr[high]) {            arr[low], arr[high] = arr[high], arr[low]        }    }    if (high - low + 1) == 3 {        median3(arr, low, high)    }}//比較空介面參數大小//用於mergeSort及其他排序演算法package mySort1import (    "log")//compare函數可以放置到其他pakcage這樣其他排序演算法可以調用//本算例compare放置在$GOPATH/src/mySort1包中//若compare與quickSort在同一包中可直接調用func compare(left, right interface{}) bool {    switch left.(type) {    //待排序數組轉為相應類型並比較    //空介面無比較    case int:        if left.(int) < right.(int) {            return true        } else {            return false        }    case float32:        if left.(float32) < right.(float32) {            return true        } else {            return false        }    case float64:        if left.(float64) < right.(float64) {            return true        } else {            return false        }    default:        log.Panicln("ilegal type: int float32 float64")    }    return false}//quickSort函數調用樣本//mergeSort用法樣本package mainimport (    "fmt"    "mySort1")func main() {    //test quickSort: int float32 float64    quickSortTest()}func quickSortTest() {    //arr1 := []int{4, 2, 1, 3, 5, 0, 8, 20, 100, 44, 50}    arr1 := []float32{4.0, 2.1, 1.1, 3.2, 5, 0, 8, 20, 100.5, 44, 50}    var arr = make([]interface{}, len(arr1))    for i, _ := range arr {        arr[i] = arr1[i]    }    fmt.Println("before meidan3: ", arr)    mySort1.QuickSort(arr, 0, len(arr)-1)    fmt.Println("after meidan3: ", arr)}

本文為基於go語言的快速排序演算法，歸併排序演算法及go語言defer用法見：https://github.com/Beginner18/myBaseCode.git

defer: src/defer

排序演算法: src/mySort1

 

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