Ordenar 3 números

Dados tres números, ¿cómo ordenarlos?

Ejemplos : 

Input  : arr[] = {3, 2, 1}
Output : arr[] = {1, 2, 3}

Input : arr[] = {6, 5, 0}
Output :arr[] = {0, 5, 6}

Una solución simple es usar la función de clasificación .  

// C++ program to sort an array of size 3
#include <algorithm>
#include <iostream>
using namespace std;
 
int main()
{
    int a[] = {10, 12, 5};
 
    sort(a, a + 3);
 
    for (int i = 0; i < 3; i++)
        cout << a[i] << " ";
 
    return 0;
}

// Java program to sort
// an array of size 3
import java.io.*;
import java .util.*;
 
class GFG
{
    public static void main (String[] args)
    {
        int a[] = {10, 12, 5};
 
        Arrays.sort(a);
 
        for (int i = 0; i < 3; i++)
            System.out.print( a[i] + " ");
    }
}
 
// This code is contributed
// by inder_verma.

# Python3 program to sort
# an array of size 3
a = [10, 12, 5]
a.sort()
for i in range(len(a)):
    print(a[i], end = ' ')
 
# This code is contributed
# by Samyukta S Hegde

// C# program to sort
// an array of size 3
using System;
class GFG
{
    public static void Main ()
    {
        int []a = {10, 12, 5};
 
        Array.Sort(a);
 
        for (int i = 0; i < 3; i++)
         Console.Write( a[i] + " ");
    }
}
 
// This code is contributed
// by chandan_jnu.

<?php
// PHP program to sort
// an array of size 3
$a = array(10, 12, 5);
 
sort($a);
 
for ($i = 0; $i < 3; $i++)
    echo $a[$i] , " ";
 
// This code is contributed
// by chandan_jnu.
?>

<script>
 
// Javascript program to sort an array of size 3
let arr = [10, 12, 5];
 
arr.sort((a, b) => a - b);
 
for (let i = 0; i < 3; i++)
document.write(arr[i] + " ");
 
// This code is contributed by Jana_Sayantan.
</script>

5 10 12

Complejidad de Tiempo : O(1)
Espacio Auxiliar : O(1)

¿Cómo escribir nuestra propia función de clasificación que haga una comparación mínima y no use variables adicionales?  
La idea es utilizar la ordenación por inserción, ya que la ordenación por inserción funciona mejor para arreglos pequeños.

// C++ program to sort an array of size 3
#include <algorithm>
#include <iostream>
using namespace std;
 
int sort3(int arr[])
{
    // Insert arr[1]
    if (arr[1] < arr[0])
       swap(arr[0], arr[1]);
 
    // Insert arr[2]
    if (arr[2] < arr[1])
    {
       swap(arr[1], arr[2]);
       if (arr[1] < arr[0])
          swap(arr[1], arr[0]);
    }
}
 
int main()
{
    int a[] = {10, 12, 5};
     
    sort3(a);
 
    for (int i = 0; i < 3; i++)
        cout << a[i] << " ";
 
    return 0;
}

// Java program to sort
// an array of size 3
import java.io.*;
import java.util.*;
 
class GFG
{
static void sort3(int arr[],
                  int temp[])
{
    // Insert arr[1]
    if (arr[1] < arr[0])
        {
            temp[0] = arr[0];
            arr[0] = arr[1];
            arr[1] = temp[0];
        }
 
    // Insert arr[2]
    if (arr[2] < arr[1])
    {
            temp[0] = arr[1];
            arr[1] = arr[2];
            arr[2] = temp[0];
             
    if (arr[1] < arr[0])
        {
            temp[0] = arr[0];
            arr[0] = arr[1];
            arr[1] = temp[0];
        }
    }
}
 
// Driver Code
public static void main(String args[])
{
    int a[] = new int[]{10, 12, 5};
    int temp1[] = new int[10];
    sort3(a, temp1);
 
    for (int i = 0; i < 3; i++)
        System.out.print( a[i] + " ");
}
}
 
// This code is contributed
// by Akanksha Rai(Abby_akku)

# Python3 program to sort an array of size 3
def sort3(arr):
     
    # Insert arr[1]
    if (arr[1] < arr[0]):
        arr[0], arr[1] = arr[1], arr[0]
         
    # Insert arr[2]
    if (arr[2] < arr[1]):
        arr[1], arr[2] = arr[2], arr[1]
        if (arr[1] < arr[0]):
            arr[1], arr[0] = arr[0], arr[1]
     
# Driver code
a = [10, 12, 5]
 
sort3(a)
 
for i in range(3):
    print(a[i],end=" ")
     
# This code is contributed by shubhamsingh10

// C# program to sort
// an array of size 3
using System;
 
class GFG {
     
static void sort3(int []arr, int []temp)
{
     
    // Insert arr[1]
    if (arr[1] < arr[0])
        {
            temp[0] = arr[0];
            arr[0] = arr[1];
            arr[1] = temp[0];
        }
 
    // Insert arr[2]
    if (arr[2] < arr[1])
    {
        temp[0] = arr[1];
        arr[1] = arr[2];
        arr[2] = temp[0];
             
        if (arr[1] < arr[0])
        {
            temp[0] = arr[0];
            arr[0] = arr[1];
            arr[1] = temp[0];
        }
    }
}
 
    // Driver Code
    public static void Main(String []args)
    {
        int []a= new int[]{10, 12, 5};
        int []temp1 = new int[10];
        sort3(a, temp1);
     
        for (int i = 0; i < 3; i++)
            Console.Write( a[i] + " ");
    }
}
 
// This code is contributed
// by Akanksha Rai(Abby_akku)

<?php
// PHP program to sort an array of size 3
function sort3(&$arr, $temp)
{
    // Insert arr[1]
    if ($arr[1] < $arr[0])
    {
        $temp[0] = $arr[0];
        $arr[0] = $arr[1];
        $arr[1] = $temp[0];
    }
 
    // Insert arr[2]
    if ($arr[2] < $arr[1])
    {
        $temp[0] = $arr[1];
        $arr[1] = $arr[2];
        $arr[2] = $temp[0];
    }
     
    if ($arr[1] < $arr[0])
    {
        $temp[0] = $arr[0];
        $arr[0] = $arr[1];
        $arr[1] = $temp[0];
    }
}
 
// Driver Code
$a = array(10, 12, 5);
$temp1 = array(10);
sort3($a, $temp1);
 
for ($i = 0; $i < 3; $i++)
    echo($a[$i] . " ");
 
// This code is contributed
// by Code_Mech.
?>

<script>
 
// Javascript program to sort an
// array of size 3
function sort3(arr, temp)
{
     
    // Insert arr[1]
    if (arr[1] < arr[0])
    {
        temp[0] = arr[0];
        arr[0] = arr[1];
        arr[1] = temp[0];
    }
 
    // Insert arr[2]
    if (arr[2] < arr[1])
    {
        temp[0] = arr[1];
        arr[1] = arr[2];
        arr[2] = temp[0];
 
        if (arr[1] < arr[0])
        {
            temp[0] = arr[0];
            arr[0] = arr[1];
            arr[1] = temp[0];
        }
    }
}
 
// Driver code
let a = [ 10, 12, 5 ];
let temp1 = [10];
sort3(a, temp1);
 
for(let i = 0; i < 3; i++)
    document.write( a[i] + " ");
     
// This code is contributed by decode2207
 
</script>

5 10 12

Complejidad de Tiempo : O(1)
Espacio Auxiliar : O(1)