midoks-Go实现的堆排序算法

堆排序（英语：Heapsort）是指利用堆这种数据结构所设计的一种排序算法。堆是一个近似完全二叉树的结构，并同时满足堆积的性质：即子结点的键值或索引总是小于（或者大于）它的父节点。

源码

package main

import (
    "fmt"
    "math/rand"
    "time"
)

const (
    num      = 10
    rangeNum = 10
)

func main() {
    randSeed := rand.New(rand.NewSource(time.Now().Unix() + time.Now().UnixNano()))
    var buf []int
    for i := 0; i < num; i++ {
        buf = append(buf, randSeed.Intn(rangeNum))
    }
    t := time.Now()

    // 堆排序
    HeapSort(buf)
    fmt.Println(buf)
    fmt.Println(time.Since(t))
}

// 堆排序
func HeapSort(buf []int) {
    temp, n := 0, len(buf)

    for i := (n - 1) / 2; i >= 0; i-- {
        MinHeapFixdown(buf, i, n)
    }

    for i := n - 1; i > 0; i-- {
        temp = buf[0]
        buf[0] = buf[i]
        buf[i] = temp
        MinHeapFixdown(buf, 0, i)
    }
}

func MinHeapFixdown(a []int, i, n int) {
    j, temp := 2*i+1, 0
    for j < n {
        if j+1 < n && a[j+1] < a[j] {
            j++
        }

        if a[i] <= a[j] {
            break
        }

        temp = a[i]
        a[i] = a[j]
        a[j] = temp

        i = j
        j = 2*i + 1
    }
}

go run heap.go

midoksdeMacBook-Pro:test midoks$ go run heap.go 
[8 8 6 5 2 1 1 1 1 0]
45.2µs