Given N, check if the number is a Fibbinary number or not. Fibbinary numbers are integers whose binary representation includes no consecutive ones.
Examples:
Input : 10
Output : YES
Explanation: 1010 is the binary representation
of 10 which does not contains any
consecutive 1's.
Input : 11
Output : NO
Explanation: 1011 is the binary representation
of 11, which contains consecutive
1's
The idea of doing this is to right shift the number, till n!=0. For every binary representation of 1, check if the last bit found was 1 or not. Get the last bit of binary representation of the integer by doing a(n&1). If the last bit of the binary representation is 1 and the previous bit before doing a right shift was also one, we encounter consecutive 1's. So we come to the conclusion that it is not a fibbinary number.
Some of the first few Fibbinary numbers are:
0, 2, 4, 8, 10, 16, 18, 20.......
// CPP program to check if a number
// is fibinnary number or not
#include <iostream>
using namespace std;
// function to check if binary
// representation of an integer
// has consecutive 1s
bool checkFibinnary(int n)
{
// stores the previous last bit
// initially as 0
int prev_last = 0;
while (n)
{
// if current last bit and
// previous last bit is 1
if ((n & 1) && prev_last)
return false;
// stores the last bit
prev_last = n & 1;
// right shift the number
n >>= 1;
}
return true;
}
// Driver code to check above function
int main()
{
int n = 10;
if (checkFibinnary(n))
cout << "YES";
else
cout << "NO";
return 0;
}
// Java program to check if a number
// is fibinnary number or not
class GFG {
// function to check if binary
// representation of an integer
// has consecutive 1s
static boolean checkFibinnary(int n)
{
// stores the previous last bit
// initially as 0
int prev_last = 0;
while (n != 0)
{
// if current last bit and
// previous last bit is 1
if ((n & 1) != 0 && prev_last != 0)
return false;
// stores the last bit
prev_last = n & 1;
// right shift the number
n >>= 1;
}
return true;
}
// Driver code to check above function
public static void main(String[] args)
{
int n = 10;
if (checkFibinnary(n) == true)
System.out.println("YES");
else
System.out.println("NO");
}
}
// This code is contributed by
// Smitha Dinesh Semwal
# Python 3 program to check if a
# number is fibinnary number or
# not
# function to check if binary
# representation of an integer
# has consecutive 1s
def checkFibinnary(n):
# stores the previous last bit
# initially as 0
prev_last = 0
while (n):
# if current last bit and
# previous last bit is 1
if ((n & 1) and prev_last):
return False
# stores the last bit
prev_last = n & 1
# right shift the number
n >>= 1
return True
# Driver code
n = 10
if (checkFibinnary(n)):
print("YES")
else:
print("NO")
# This code is contributed by Smitha Dinesh Semwal
// C# program to check if a number
// is fibinnary number or not
using System;
class GFG {
// function to check if binary
// representation of an integer
// has consecutive 1s
static bool checkFibinnary(int n)
{
// stores the previous last bit
// initially as 0
int prev_last = 0;
while (n != 0)
{
// if current last bit and
// previous last bit is 1
if ((n & 1) != 0 && prev_last != 0)
return false;
// stores the last bit
prev_last = n & 1;
// right shift the number
n >>= 1;
}
return true;
}
// Driver code to check above function
public static void Main()
{
int n = 10;
if (checkFibinnary(n) == true)
Console.WriteLine("YES");
else
Console.WriteLine("NO");
}
}
// This code is contributed by vt_m.
<?php
// PHP program to check if a number
// is fibinnary number or not
// function to check if binary
// representation of an integer
// has consecutive 1s
function checkFibinnary($n)
{
// stores the previous last bit
// initially as 0
$prev_last = 0;
while ($n)
{
// if current last bit and
// previous last bit is 1
if (($n & 1) && $prev_last)
return false;
// stores the last bit
$prev_last = $n & 1;
// right shift the number
$n >>= 1;
}
return true;
}
// Driver code
$n = 10;
if (checkFibinnary($n))
echo "YES";
else
echo "NO";
// This code is contributed by mits
?>
<script>
// javascript program to check if a number
// is fibinnary number or not
// function to check if binary
// representation of an integer
// has consecutive 1s
function checkFibinnary(n) {
// stores the previous last bit
// initially as 0
var prev_last = 0;
while (n != 0) {
// if current last bit and
// previous last bit is 1
if ((n & 1) != 0 && prev_last != 0)
return false;
// stores the last bit
prev_last = n & 1;
// right shift the number
n >>= 1;
}
return true;
}
// Driver code to check above function
var n = 10;
if (checkFibinnary(n) == true)
document.write("YES");
else
document.write("NO");
// This code contributed by Rajput-Ji
</script>
Output:
YES
Time Complexity: O(logN), as we are using a loop to traverse logN times, we are decrementing by floor division of 2 (as right shifting a number by 1 is equivalent to floor division by 2) in each iteration therefore the loop iterates logN times.
Auxiliary Space: O(1), as we are not using any extra space.
Fibbinary Numbers (No consecutive 1s in binary) – O(1) Approach