Establecer el bit más a la izquierda no establecido

Dado un número entero, establezca el bit no establecido más a la izquierda. El bit desarmado más a la izquierda es el primer bit desarmado después del bit de armado más significativo. Si todos los bits (después del bit establecido más significativo) están establecidos, devuelva el número.

Ejemplos: 

Input : 10
Output : 14
10 = 1 0 1 0    // 10 binary
14 = 1 1 1 0    // after set left most unset bit

Input : 15      
Output : 15
15 = 1 1 1 1    // 15 binary
15 = 1 1 1 1    // because all bits are set

Enfoque:- 
1. Devuelva el número si todos los bits están configurados. 
2. Atraviese todo el bit para obtener el último bit desarmado. 
3. Tomar OR con el número original y el bit desarmado.

A continuación se muestra la implementación del enfoque. 

// C++ program to set the leftmost unset bit
#include <iostream>
using namespace std;
 
// set left most unset bit
int setleftmostunsetbit(int n)
{
    // if number contain all
    // 1 then return n
    if ((n & (n + 1)) == 0)
        return n;
 
    // Find position of leftmost unset bit.
    int pos = 0;
    for (int temp=n, count=0; temp>0;
                        temp>>=1, count++)
 
        // if temp L.S.B is zero
        // then unset bit pos is
        // change
        if ((temp & 1) == 0)
            pos = count;  
 
    // return OR of number and
    // unset bit pos
    return (n | (1 << (pos)));
}
 
// Driver Function
int main()
{
    int n = 10;
    cout << setleftmostunsetbit(n);
    return 0;
}

// Java program to set
// the leftmost unset bit
import java.io.*;
 
class GFG
{
    // set left most unset bit
    static int setleftmostunsetbit(int n)
    {
        // if number contain all
        // 1 then return n
        if ((n & (n + 1)) == 0)
            return n;
     
        // Find position of leftmost unset bit.
        int pos = 0;
        for (int temp = n, count = 0; temp > 0;
                           temp >>= 1, count++)
     
            // if temp L.S.B is zero
            // then unset bit pos is
            // change
            if ((temp & 1) == 0)
                pos = count;
     
        // return OR of number and
        // unset bit pos
        return (n | (1 << (pos)));
    }
     
    // Driver Function
    public static void main (String[] args)
    {
        int n = 10;
        System.out.println(setleftmostunsetbit(n));
    }
}
 
// This code is contributed by Ansu Kumari

# Python program to set the leftmost unset bit
 
# Set left most unset bit
def setleftmostunsetbit(n):
    # if number contain all
    # 1 then return n
    if not (n & (n + 1)):
        return n
 
    # Find position of leftmost unset bit
    pos, temp, count = 0, n, 0
     
    while temp:
        # if temp L.S.B is zero
        # then unset bit pos is
        # change
        if not (temp & 1):
            pos = count
             
        count += 1; temp>>=1
 
    # return OR of number and
    # unset bit pos
    return (n | (1 << (pos)))
 
 
# Driver Function
n = 10
print(setleftmostunsetbit(n))
 
# This code is contributed by Ansu Kumari

// C# program to set
// the leftmost unset bit
using System;
 
class GFG
{
    // set left most unset bit
    static int setleftmostunsetbit(int n)
    {
        // if number contain all
        // 1 then return n
        if ((n & (n + 1)) == 0)
            return n;
     
        // Find position of leftmost unset bit.
        int pos = 0;
        for (int temp = n, count = 0; temp > 0;
                            temp >>= 1, count++)
     
            // if temp L.S.B is zero
            // then unset bit pos is
            // change
            if ((temp & 1) == 0)
                pos = count;
     
        // return OR of number and
        // unset bit pos
        return (n | (1 << (pos)));
    }
     
    // Driver Function
    public static void Main ()
    {
        int n = 10;
        Console.WriteLine(setleftmostunsetbit(n));
    }
}
 
// This code is contributed by vt_m

<?php
// php program to set the
// leftmost unset bit
 
// set left most unset bit
function setleftmostunsetbit($n)
{
     
    // if number contain all
    // 1 then return n
    if (($n & ($n + 1)) == 0)
        return $n;
 
    // Find position of leftmost
    // unset bit.
    $pos = 0;
    for ($temp = $n, $count = 0; $temp > 0;
                     $temp >>= 1, $count++)
 
        // if temp L.S.B is zero
        // then unset bit pos is
        // change
        if (($temp & 1) == 0)
            $pos = $count;
 
    // return OR of number
    // and unset bit pos
    return ($n | (1 << ($pos)));
}
 
    // Driver code
    $n = 10;
    echo setleftmostunsetbit($n);
 
//This code is contributed by mits
?>

<script>
 
// Javascript program to set the
// leftmost unset bit
 
// Set left most unset bit
function setleftmostunsetbit(n)
{
     
    // If number contain all
    // 1 then return n
    if ((n & (n + 1)) == 0)
        return n;
 
    // Find position of leftmost unset bit.
    let pos = 0;
    for(let temp = n, count = 0; temp > 0;
            temp >>= 1, count++)
 
        // If temp L.S.B is zero
        // then unset bit pos is
        // change
        if ((temp & 1) == 0)
            pos = count;
 
    // Return OR of number and
    // unset bit pos
    return (n | (1 << (pos)));
}
 
// Driver Code
let n = 10;
 
document.write(setleftmostunsetbit(n));
 
// This code is contributed by Manoj.
 
</script>

Producción: 

14

Complejidad del tiempo: O(log ₂ n)

Espacio Auxiliar: O(1)