题目：

题解：

func partition(a []int, l, r int) int {
    x := a[r]
    i := l - 1
    for j := l; j < r; j++ {
        if a[j] <= x {
            i++
            a[i], a[j] = a[j], a[i]
        }
    }
    a[i+1], a[r] = a[r], a[i+1]
    return i + 1
}

func randomPartition(a []int, l, r int) int {
    i := rand.Intn(r-l+1) + l
    a[i], a[r] = a[r], a[i]
    return partition(a, l, r)
}

func quickSelect(a []int, l, r, index int) int {
    q := randomPartition(a, l, r)
    if q == index {
        return a[q]
    }
    if q < index {
        return quickSelect(a, q+1, r, index)
    }
    return quickSelect(a, l, q-1, index)
}

func minMoves2(nums []int) (ans int) {
    rand.Seed(time.Now().UnixNano())
    x := quickSelect(nums, 0, len(nums)-1, len(nums)/2)
    for _, num := range nums {
        ans += abs(num - x)
    }
    return
}

func abs(x int) int {
    if x < 0 {
        return -x
    }
    return x
}