v/examples/quick_sort.v

41 lines
915 B
V

import rand
const (
gen_len = 1000 // how many random numbers to generate
gen_max = 10000 // max of the generated numbers
)
fn main() {
mut arr := []int{}
for _ in 0..gen_len {
arr << rand.intn(gen_max)
}
println('length of random array is $arr.len')
println('before quick sort whether array is sorted: ${is_sorted(arr)}')
quick_sort(mut arr, 0, arr.len-1)
println('after quick sort whether array is sorted: ${is_sorted(arr)}')
}
fn quick_sort(mut arr []int, l int, r int) {
if l>=r { return }
mut sep := l // what is sep: [...all_value<arr[sep]...sep...all_value>=arr[sep]...]
for i in l+1..r+1 {
if arr[i] < arr[l] {
sep++
arr[i], arr[sep] = arr[sep], arr[i]
}
}
arr[l], arr[sep] = arr[sep], arr[l]
quick_sort(mut arr, l, sep-1)
quick_sort(mut arr, sep+1, r)
}
fn is_sorted(arr []int) bool {
for i in 0..arr.len-1 {
if arr[i] > arr[i+1] {
return false
}
}
return true
}