// Select will rearrange data so that data[k] is the kth smallest element.
// data[0 .. k-1] <= data[k] <= data[k+1 .. n]
func Select(data sort.Interface, k int) (id int) {
n := data.Len()
if k < 0 || k >= n {
panic("Select with invalid k")
}
rand.Shuffle(data)
lo := 0
hi := n - 1
for hi > lo {
i := Partition(data, lo, hi)
if i > k {
hi = i - 1
} else if i < k {
lo = i + 1
} else {
return i
}
}
return lo
}
// QuickSort3Way sorts the slice using quicksort with 3way partition.
func QuickSort3Way(data sort.Interface) {
rand.Shuffle(data)
quickSort3Way(data, 0, data.Len()-1)
}