quicksort.go

package main

import "fmt"

func quicksort(nums []int) {
    if nums == nil || len(nums) <= 1 { 
        return 
    }   

    quicksort2(nums, 0, len(nums) - 1)
}

func quicksort2(nums []int, start, end int) {
    if start >= end {
        return 
    }   
    
    pi := partition(nums, start, end)
    quicksort2(nums, start, pi-1)
    quicksort2(nums, pi+1, end)
}


func partition(nums []int, start, end int) int {
    pi := start
    pivot := nums[end]

    for i := start; i < end; i++ {
        if nums[i] < pivot {
            nums[i], nums[pi] = nums[pi], nums[i]
            pi += 1
        }
    }   

    nums[end], nums[pi] = nums[pi], nums[end]

    return pi
}

func main() {
    nums := []int{2, 4, 3, 1, 5, 8, 10, 110, 1, 3, 4, 5, -1} 

    quicksort(nums)

    fmt.Println(nums)
}
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