Comprobar si un número tiene bits en patrón alternativo | Serie 1

Dado un entero n > 0, la tarea es encontrar si este entero tiene un patrón alternativo en su representación de bits. Por ejemplo, 5 tiene un patrón alternativo, es decir, 101. 
Escriba «Sí» si tiene un patrón alternativo; de lo contrario, «No». Aquí el patrón alternativo puede ser como 0101 o 1010.

Ejemplos: 

Input :  15
Output :  No
Explanation: Binary representation of 15 is 1111.

Input :  10
Output :  Yes
Explanation: Binary representation of 10 is 1010.

Un enfoque simple es encontrar su equivalente binario y luego verificar sus bits.  

// C++ program to find if a number has alternate bit pattern
#include <bits/stdc++.h>
using namespace std;
 
// Returns true if n has alternate bit pattern else false
bool findPattern(int n)
{
    // Store last bit
    int prev = n % 2;
    n = n / 2;
    // Traverse through remaining bits
    while (n > 0) {
        int curr = n % 2;
        // If current bit is same as previous
        if (curr == prev)
            return false;
        prev = curr;
        n = n / 2;
    }
    return true;
}
 
// Driver code
int main()
{
    int n = 10;
    if (findPattern(n))
        cout << "Yes";
    else
        cout << "No";
    return 0;
}
 
// This code is contributed by Sania Kumari Gupta (kriSania804)

// C program to find if a number has alternate bit pattern
#include <stdbool.h>
#include <stdio.h>
// Returns true if n has alternate bit pattern else false
bool findPattern(int n)
{
    // Store last bit
    int prev = n % 2;
    n = n / 2;
    // Traverse through remaining bits
    while (n > 0) {
        int curr = n % 2;
        // If current bit is same as previous
        if (curr == prev)
            return false;
        prev = curr;
        n = n / 2;
    }
    return true;
}
 
// Driver code
int main()
{
    int n = 10;
    if (findPattern(n))
        printf("Yes");
    else
        printf("No");
    return 0;
}
 
// This code is contributed by Sania Kumari Gupta
// (kriSania804)

// Java program to find if a number has alternate bit
// pattern
 
class Test {
    // Returns true if n has alternate bit pattern
    // else false
    static boolean findPattern(int n)
    {
        // Store last bit
        int prev = n % 2;
        n = n / 2;
        // Traverse through remaining bits
        while (n > 0) {
            int curr = n % 2;
            // If current bit is same as previous
            if (curr == prev)
                return false;
            prev = curr;
            n = n / 2;
        }
        return true;
    }
 
    // Driver method
    public static void main(String args[])
    {
        int n = 10;
        System.out.println(findPattern(n) ? "Yes" : "No");
    }
}
 
// This code is contributed by Sania Kumari Gupta
// (kriSania804)

# Python3 program to find if a number
# has alternate bit pattern
 
# Returns true if n has alternate
# bit pattern else false
def findPattern(n):
 
    # Store last bit
    prev = n % 2
    n = n // 2
 
    # Traverse through remaining bits
    while (n > 0):
     
        curr = n % 2
 
        # If current bit is same as previous
        if (curr == prev):
            return False
 
        prev = curr
        n = n // 2
     
    return True
 
# Driver code
n = 10
print("Yes") if(findPattern(n)) else print("No")
 
# This code is contributed by Anant Agarwal.

// Program to find if a number
// has alternate bit pattern
using System;
 
class Test {
 
    // Returns true if n has alternate
    // bit pattern else returns false
    static bool findPattern(int n)
    {
        // Store last bit
        int prev = n % 2;
        n = n / 2;
 
        // Traverse through remaining bits
        while (n > 0) {
            int curr = n % 2;
 
            // If current bit is same as previous
            if (curr == prev)
                return false;
 
            prev = curr;
            n = n / 2;
        }
 
        return true;
    }
 
    // Driver method
    public static void Main()
    {
        int n = 10;
        Console.WriteLine(findPattern(n) ? "Yes" : "No");
    }
}
 
// This code is contributed by Anant Agarwal.

<?php
// PHP program to find if a
// number has alternate
// bit pattern
 
// Returns true if n has
// alternate bit pattern
// else false
function findPattern($n)
{
     
    // Store last bit
    $prev = $n % 2;
    $n = $n / 2;
 
    // Traverse through
    // remaining bits
    while ($n > 0)
    {
        $curr = $n % 2;
 
        // If current bit is
        // same as previous
        if ($curr == $prev)
        return false;
 
        $prev = $curr;
        $n = floor($n / 2);
    }
 
    return true;
}
 
    // Driver code
    $n = 10;
    if (findPattern($n))
        echo "Yes";
    else
        echo "No";
         
    return 0;
 
// This code is contributed by nitin mittal.
?>

<script>
 
// Javascript program to find if a number
// has alternate bit pattern
 
// Returns true if n has alternate
// bit pattern else false
function findPattern(n)
{
     
    // Store last bit
    let prev = n % 2;
    n = Math.floor(n / 2);
 
    // Traverse through remaining bits
    while (n > 0)
    {
        let curr = n % 2;
 
        // If current bit is
        // same as previous
        if (curr == prev)
            return false;
 
        prev = curr;
        n = Math.floor(n / 2);
    }
    return true;
}
 
// Driver code
let n = 10;
if (findPattern(n))
    document.write("Yes");
else
    document.write("No");
     
// This code is contributed by gfgking
 
</script>

Producción: 

Yes

Complejidad del tiempo: O(log ₂ n)

Espacio Auxiliar: O(1)

Referencia:  
http://stackoverflow.com/questions/38690278/program-to-check-whether-the-given-integer-has-an-alternate-pattern

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