156 lines
2.8 KiB
Go
156 lines
2.8 KiB
Go
// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
|
|
|
|
package utils
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"golang.org/x/exp/constraints"
|
|
"golang.org/x/exp/slices"
|
|
)
|
|
|
|
var _ = fmt.Print
|
|
|
|
func Reverse[T any](s []T) []T {
|
|
for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
|
|
s[i], s[j] = s[j], s[i]
|
|
}
|
|
return s
|
|
}
|
|
|
|
func Reversed[T any](s []T) []T {
|
|
ans := make([]T, len(s))
|
|
for i, x := range s {
|
|
ans[len(s)-1-i] = x
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Remove[T comparable](s []T, q T) []T {
|
|
idx := slices.Index(s, q)
|
|
if idx > -1 {
|
|
return slices.Delete(s, idx, idx+1)
|
|
}
|
|
return s
|
|
}
|
|
|
|
func RemoveAll[T comparable](s []T, q T) []T {
|
|
ans := s
|
|
for {
|
|
idx := slices.Index(ans, q)
|
|
if idx < 0 {
|
|
break
|
|
}
|
|
ans = slices.Delete(ans, idx, idx+1)
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Filter[T any](s []T, f func(x T) bool) []T {
|
|
ans := make([]T, 0, len(s))
|
|
for _, x := range s {
|
|
if f(x) {
|
|
ans = append(ans, x)
|
|
}
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Map[T any, O any](f func(x T) O, s []T) []O {
|
|
ans := make([]O, 0, len(s))
|
|
for _, x := range s {
|
|
ans = append(ans, f(x))
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Repeat[T any](x T, n int) []T {
|
|
ans := make([]T, n)
|
|
for i := 0; i < n; i++ {
|
|
ans[i] = x
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Sort[T any](s []T, less func(a, b T) bool) []T {
|
|
slices.SortFunc(s, less)
|
|
return s
|
|
}
|
|
|
|
func StableSort[T any](s []T, less func(a, b T) bool) []T {
|
|
slices.SortStableFunc(s, less)
|
|
return s
|
|
}
|
|
|
|
func sort_with_key[T any, C constraints.Ordered](stable bool, s []T, key func(a T) C) []T {
|
|
type t struct {
|
|
key C
|
|
val T
|
|
}
|
|
temp := make([]t, len(s))
|
|
for i, x := range s {
|
|
temp[i].val, temp[i].key = x, key(x)
|
|
}
|
|
if stable {
|
|
slices.SortStableFunc(temp, func(a, b t) bool { return a.key < b.key })
|
|
} else {
|
|
slices.SortFunc(temp, func(a, b t) bool { return a.key < b.key })
|
|
}
|
|
for i, x := range temp {
|
|
s[i] = x.val
|
|
}
|
|
return s
|
|
}
|
|
|
|
func SortWithKey[T any, C constraints.Ordered](s []T, key func(a T) C) []T {
|
|
return sort_with_key(false, s, key)
|
|
}
|
|
|
|
func StableSortWithKey[T any, C constraints.Ordered](s []T, key func(a T) C) []T {
|
|
return sort_with_key(true, s, key)
|
|
}
|
|
|
|
func Max[T constraints.Ordered](a T, items ...T) (ans T) {
|
|
ans = a
|
|
for _, q := range items {
|
|
if q > ans {
|
|
ans = q
|
|
}
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Min[T constraints.Ordered](a T, items ...T) (ans T) {
|
|
ans = a
|
|
for _, q := range items {
|
|
if q < ans {
|
|
ans = q
|
|
}
|
|
}
|
|
return ans
|
|
}
|
|
|
|
func Memset[T any](dest []T, pattern ...T) []T {
|
|
if len(pattern) == 0 {
|
|
var zero T
|
|
switch any(zero).(type) {
|
|
case byte: // special case this as the compiler can generate efficient code for memset of a byte slice to zero
|
|
bd := any(dest).([]byte)
|
|
for i := range bd {
|
|
bd[i] = 0
|
|
}
|
|
default:
|
|
for i := range dest {
|
|
dest[i] = zero
|
|
}
|
|
}
|
|
return dest
|
|
}
|
|
bp := copy(dest, pattern)
|
|
for bp < len(dest) {
|
|
copy(dest[bp:], dest[:bp])
|
|
bp *= 2
|
|
}
|
|
return dest
|
|
}
|