排序算法——选择排序【代码实现】
ActionScript
function selectionSort(input: Array):Array {
//find the i'th element
for (var i:uint = 0; i < input.length; i++) {
//set minIndex to an arbitrary value
var minIndex:uint=i;
//find the smallest number
for (var j:uint = i; j < input.length; j++) {
if (input[j]C
#include C++
#include C#
class SelectionSort<T> where T : IComparable {
public T[] Sort(T[] list) {
int k;
T temp;
for (int i = 0; i < list.Length; i++) {
k = i;
for (int j=i + 1; j < list.Length; j++) {
if (list[j].CompareTo(list[k]) < 0) {
k = j;
}
}
temp = list[i];
list[i] = list[k];
list[k] = temp;
}
return list;
}
}
Go
package main
import "fmt"
var a = []int{170, 45, 75, -90, -802, 24, 2, 66}
func main() {
fmt.Println("before:", a)
selectionSort(a)
fmt.Println("after: ", a)
}
func selectionSort(a []int) {
last := len(a) - 1
for i := 0; i < last; i++ {
aMin := a[i]
iMin := i
for j := i + 1; j < len(a); j++ {
if a[j] < aMin {
aMin = a[j]
iMin = j
}
}
a[i], a[iMin] = aMin, a[i]
}
}
通用版本
package main
import (
"sort"
"fmt"
)
var a = []int{170, 45, 75, -90, -802, 24, 2, 66}
func main() {
fmt.Println("before:", a)
selectionSort(sort.IntSlice(a))
fmt.Println("after: ", a)
}
func selectionSort(a sort.Interface) {
last := a.Len() - 1
for i := 0; i < last; i++ {
iMin := i
for j := i + 1; j < a.Len(); j++ {
if a.Less(j, iMin) {
iMin = j
}
}
a.Swap(i, iMin)
}
}
Java
public static void sort(int[] nums){
for(int currentPlace = 0;currentPlace<nums.length-1;currentPlace++){
int smallest = Integer.MAX_VALUE;
int smallestAt = currentPlace+1;
for(int check = currentPlace; check<nums.length;check++){
if(nums[check]<smallest){
smallestAt = check;
smallest = nums[check];
}
}
int temp = nums[currentPlace];
nums[currentPlace] = nums[smallestAt];
nums[smallestAt] = temp;
}
}
JavaScript
function selectionSort(nums) {
var len = nums.length;
for(var i = 0; i < len; i++) {
var minAt = i;
for(var j = i + 1; j < len; j++) {
if(nums[j] < nums[minAt])
minAt = j;
}
if(minAt != i) {
var temp = nums[i];
nums[i] = nums[minAt];
nums[minAt] = temp;
}
}
return nums;
}
Julia
function selectionsort!(arr::Vector{<:Real})
len = length(arr)
if len < 2 return arr end
for i in 1:len-1
lmin, j = findmin(arr[i+1:end])
if lmin < arr[i]
arr[i+j] = arr[i]
arr[i] = lmin
end
end
return arr
end
v = rand(-10:10, 10)
println("# unordered: $v\n -> ordered: ", selectionsort!(v))
Kotlin
fun <T : Comparable<T>> Array<T>.selection_sort() {
for (i in 0..size - 2) {
var k = i
for (j in i + 1..size - 1)
if (this[j] < this[k])
k = j
if (k != i) {
val tmp = this[i]
this[i] = this[k]
this[k] = tmp
}
}
}
fun main(args: Array<String>) {
val i = arrayOf(4, 9, 3, -2, 0, 7, -5, 1, 6, 8)
i.selection_sort()
println(i.joinToString())
val s = Array(i.size, { -i[it].toShort() })
s.selection_sort()
println(s.joinToString())
val c = arrayOf('z', 'h', 'd', 'c', 'a')
c.selection_sort()
println(c.joinToString())
}
MATLAB / Octave
function list = selectionSort(list)
listSize = numel(list);
for i = (1:listSize-1)
minElem = list(i);
minIndex = i;
%This for loop can be vectorized, but there will be no significant
%increase in sorting efficiency.
for j = (i:listSize)
if list(j) <= minElem
minElem = list(j);
minIndex = j;
end
end
if i ~= minIndex
list([minIndex i]) = list([i minIndex]); %Swap
end
end %for
end %selectionSort
Perl
sub selection_sort
{my @a = @_;
foreach my $i (0 .. $#a - 1)
{my $min = $i + 1;
$a[$_] < $a[$min] and $min = $_ foreach $min .. $#a;
$a[$i] > $a[$min] and @a[$i, $min] = @a[$min, $i];}
return @a;}
Perl 6
sub selection_sort ( @a is copy ) {
for 0 ..^ @a.end -> $i {
my $min = [ $i+1 .. @a.end ].min: { @a[$_] };
@a[$i, $min] = @a[$min, $i] if @a[$i] > @a[$min];
}
return @a;
}
my @data = 22, 7, 2, -5, 8, 4;
say 'input = ' ~ @data;
say 'output = ' ~ @data.&selection_sort;
PHP
- 迭代：
function selection_sort(&$arr) {
$n = count($arr);
for($i = 0; $i < count($arr); $i++) {
$min = $i;
for($j = $i + 1; $j < $n; $j++){
if($arr[$j] < $arr[$min]){
$min = $j;
}
}
list($arr[$i],$arr[$min]) = array($arr[$min],$arr[$i]);
}
}
- 递归
function selectionsort($arr,$result=array()){
if(count($arr) == 0){
return $result;
}
$nresult = $result;
$nresult[] = min($arr);
unset($arr[array_search(min($arr),$arr)]);
return selectionsort($arr,$nresult);
}
PowerShell
Function SelectionSort( [Array] $data )
{
$datal=$data.length-1
0..( $datal - 1 ) | ForEach-Object {
$min = $data[ $_ ]
$mini = $_
( $_ + 1 )..$datal | ForEach-Object {
if( $data[ $_ ] -lt $min ) {
$min = $data[ $_ ]
$mini = $_
}
}
$temp = $data[ $_ ]
$data[ $_ ] = $min
$data[ $mini ] = $temp
}
$data
}
$l = 100; SelectionSort( ( 1..$l | ForEach-Object { $Rand = New-Object Random }{ $Rand.Next( 0, $l - 1 ) } ) )
Python
def selection_sort(lst):
for i, e in enumerate(lst):
mn = min(range(i,len(lst)), key=lst.__getitem__)
lst[i], lst[mn] = lst[mn], e
return lst
R
- 循环
selectionsort.loop <- function(x)
{
lenx <- length(x)
for(i in seq_along(x))
{
mini <- (i - 1) + which.min(x[i:lenx])
start_ <- seq_len(i-1)
x <- c(x[start_], x[mini], x[-c(start_, mini)])
}
x
}
- 递归
selectionsort.rec <- function(x)
{
if(length(x) > 1)
{
mini <- which.min(x)
c(x[mini], selectionsort(x[-mini]))
} else x
}
Ruby
class Array
def selectionsort!
for i in 0..length-2
min_idx = i
for j in (i+1)...length
min_idx = j if self[j] < self[min_idx]
end
self[i], self[min_idx] = self[min_idx], self[i]
end
self
end
end
ary = [7,6,5,9,8,4,3,1,2,0]
p ary.selectionsort!
# => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Rust
fn selection_sort(array: &mut [i32]) {
let mut min;
for i in 0..array.len() {
min = i;
for j in (i+1)..array.len() {
if array[j] < array[min] {
min = j;
}
}
let tmp = array[i];
array[i] = array[min];
array[min] = tmp;
}
}
fn main() {
let mut array = [ 9, 4, 8, 3, -5, 2, 1, 6 ];
println!("The initial array is {:?}", array);
selection_sort(&mut array);
println!(" The sorted array is {:?}", array);
}
Scala
def swap(a: Array[Int], i1: Int, i2: Int) = { val tmp = a(i1); a(i1) = a(i2); a(i2) = tmp }
def selectionSort(a: Array[Int]) =
for (i <- 0 until a.size - 1)
swap(a, i, (i + 1 until a.size).foldLeft(i)((currMin, index) =>
if (a(index) < a(currMin)) index else currMin))
Swift
func selectionSort(inout arr:[Int]) {
var min:Int
for n in 0..<arr.count {
min = n
for x in n+1..<arr.count {
if (arr[x] < arr[min]) {
min = x
}
}
if min != n {
let temp = arr[min]
arr[min] = arr[n]
arr[n] = temp
}
}
}
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