Imprime un número estrictamente menor que un número dado tal que todos sus dígitos sean distintos.

Dado un número positivo n, imprima un número menor que n tal que todos sus dígitos sean distintos.
Ejemplos: 
 

Input : 1134
Output : 1098
1098  is the largest number smaller than
1134 such that all digits are distinct.

Input : 4559
Output : 4539

El problema se puede resolver fácilmente usando el conteo. En primer lugar, recorra los números menores que n y para cada número cuente la frecuencia de los dígitos usando la array de conteo. Si todos los dígitos ocurren solo una vez, imprimimos ese número. La respuesta siempre existe, por lo que no hay problema de bucle infinito.
 

C++

// CPP program to find a number less than
// n such that all its digits are distinct
#include <bits/stdc++.h>
using namespace std;
 
// Function to find a number less than
// n such that all its digits are distinct
int findNumber(int n)
{
    // looping through numbers less than n
    for (int i = n - 1; >=0 ; i--) {
 
        // initializing a hash array
        int count[10] = { 0 };
 
        int x = i; // creating a copy of i
 
        // initializing variables to compare lengths of digits
        int count1 = 0, count2 = 0;
 
        // counting frequency of the digits
        while (x) {
            count[x % 10]++;
            x /= 10;
            count1++;
        }
 
        // checking if each digit is present once
        for (int j = 0; j < 10; j++) {
            if (count[j] == 1)
                count2++;
        }        
        if (count1 == count2)
            return i;
    }
}
 
// Driver code
int main()
{
    int n = 8490;
    cout << findNumber(n);
    return 0;
}

Java

// Java program to find a number less than
// n such that all its digits are distinct
 
class GFG{
// Function to find a number less than
// n such that all its digits are distinct
static int findNumber(int n)
{
    // looping through numbers less than n
    for (int i = n - 1;i >=0 ; i--) {
 
        // initializing a hash array
        int[] count=new int[10];
 
        int x = i; // creating a copy of i
 
        // initializing variables to compare lengths of digits
        int count1 = 0, count2 = 0;
 
        // counting frequency of the digits
        while (x>0) {
            count[x % 10]++;
            x /= 10;
            count1++;
        }
 
        // checking if each digit is present once
        for (int j = 0; j < 10; j++) {
            if (count[j] == 1)
                count2++;
        }        
        if (count1 == count2)
            return i;
    }
    return -1;
}
 
// Driver code
public static void main(String[] args)
{
    int n = 8490;
    System.out.println(findNumber(n));
}
}
// This code is contributed by mits

Python3

# python 3 program to find a number less than
# n such that all its digits are distinct
 
# Function to find a number less than
# n such that all its digits are distinct
def findNumber(n):
    # looping through numbers less than n
    i = n-1
    while(i>=0):
        # initializing a hash array
        count = [0 for i in range(10)]
 
        x = i
        # creating a copy of i
 
        # initializing variables to compare lengths of digits
        count1 = 0
        count2 = 0
 
        # counting frequency of the digits
        while (x):
         
            count[x%10] += 1
            x = int(x / 10)
            count1 += 1
         
        # checking if each digit is present once
        for j in range(0,10,1):
            if (count[j] == 1):
                count2 += 1
                 
        if (count1 == count2):
            return i
        i -= 1
     
# Driver code
if __name__ == '__main__':
 
    n = 8490
    print(findNumber(n))
 
# This code is implemented by
# Surendra_Gangwar

C#

// C# program to find a number less than
// n such that all its digits are distinct
using System;
 
class GFG
{
     
// Function to find a number less than
// n such that all its digits are distinct
static int findNumber(int n)
{
    // looping through numbers less than n
    for (int i = n - 1; i >= 0; i--)
    {
 
        // initializing a hash array
        int[] count = new int[10];
 
        int x = i; // creating a copy of i
 
        // initializing variables to compare
        // lengths of digits
        int count1 = 0, count2 = 0;
 
        // counting frequency of the digits
        while (x > 0)
        {
            count[x % 10]++;
            x /= 10;
            count1++;
        }
 
        // checking if each digit is
        // present once
        for (int j = 0; j < 10; j++)
        {
            if (count[j] == 1)
                count2++;
        }    
        if (count1 == count2)
            return i;
    }
    return -1;
}
 
// Driver code
static public void Main ()
{
    int n = 8490;
    Console.WriteLine(findNumber(n));
}
}
 
// This code is contributed by akt_mit

PHP

<?php
// PHP program to find a number less than
// n such that all its digits are distinct
 
// Function to find a number less than
// n such that all its digits are distinct
function findNumber($n)
{
    // looping through numbers less than n
    for ($i = $n - 1;$i >= 0 ; $i--)
    {
 
        // initializing a hash array
        $count = array_fill(0, 10, 0);
 
        $x = $i; // creating a copy of i
 
        // initializing variables to
        // compare lengths of digits
        $count1 = 0; $count2 = 0;
 
        // counting frequency of the digits
        while ($x)
        {
            $count[$x % 10]++;
            $x = (int)($x / 10);
            $count1++;
        }
 
        // checking if each digit
        // is present once
        for ($j = 0; $j < 10; $j++)
        {
            if ($count[$j] == 1)
                $count2++;
        }    
        if ($count1 == $count2)
            return $i;
    }
}
 
// Driver code
$n = 8490;
echo findNumber($n);
 
// This code is contributed
// by Akanksha Rai
?>

Javascript

<script>
 
// Javascript program to find a number less than
// n such that all its digits are distinct
 
// Function to find a number less than
// n such that all its digits are distinct
function findNumber(n)
{
    // looping through numbers less than n
    for (i = n - 1;i >=0 ; i--) {
 
        // initializing a hash array
        var count=Array.from({length: 10}, (_, i) => 0);
 
        var x = i; // creating a copy of i
 
        // initializing variables to compare lengths of digits
        var count1 = 0, count2 = 0;
 
        // counting frequency of the digits
        while (x>0) {
            count[x % 10]++;
            x = parseInt(x/10);
            count1++;
        }
 
        // checking if each digit is present once
        for (j = 0; j < 10; j++) {
            if (count[j] == 1)
                count2++;
        }        
        if (count1 == count2)
            return i;
    }
    return -1;
}
 
// Driver code
var n = 8490;
document.write(findNumber(n));
 
 
// This code is contributed by 29AjayKumar
 
</script>
Producción: 

8479

 

Complejidad de tiempo: O (N * log 10 N) donde n es el número de elementos en una array dada. Como, estamos usando un ciclo para atravesar N veces, por lo que nos costará O (N) tiempo y estamos usando un ciclo while que costará O (logN) a medida que disminuimos por división de piso de 10 cada vez.
Espacio auxiliar: O(1), ya que no estamos utilizando ningún espacio adicional.

Publicación traducida automáticamente

Artículo escrito por rupesh_rao y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA

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