第k个数-golang

package main

import (
    "fmt"
    "log"
)

func main() {
    var n, k int
    fmt.Scanf("%d\n", &n)
    fmt.Scanf("%d\n", &k)
    q := make([]int, n)
    for i := 0; i < n; i++ {
        fmt.Scanf("%d", &q[i])
    }

    quickSelect(q, 0, len(q)-1, k)
    log.Println(q[k-1])
}



func quickSelect(data []int, l, r, k int) {
    if l >= r{
        return
    }

    x := data[(l+r)>>1]
    i, j := l-1, r+1
    for i < j{
        for{
            i++
            if data[i] >= x{
                break
            }
        }
        for {
            j--
            if data[j] <= x{
                break
            }
        }
        if i < j{
            data[i], data[j] = data[j], data[i]
        }
    }

    if j >= k{
        quickSelect(data, l, j, k)
    }else {
        quickSelect(data, j+1, r, k)
    }
    return
}