Binary String of given length that without a palindrome of size 3

Given an integer n. Find a string of characters ‘a’ and ‘b’ such that the string doesn’t contain any palindrome of length 3.

Examples:

Input : 3
Output : "aab"
Explanation:
aab is not a palindrome.

Input : 5
Output : aabba
Explanation:
aabba does not contain a palindrome
of size 3.



The approach here is that we can use this string ‘aabb’ and print the characters of the string according to the given integer.

We need to make make sure that every third 
character is different.

If we perform operation AND on i and 2 where
i = 0 to any positive integer. It will generate
a pattern 0, 0, 2, 2, 0, 0, 2, 2,... 
0 AND 2 = 0
1 AND 2 = 0
2 AND 2 = 2
3 AND 2 = 2
4 AND 2 = 0 //repeat the pattern.

Below is the code of above approach.

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// CPP program find a binary string of 
// given length that doesn't contain
// a palindrome of size 3.
#include <bits/stdc++.h>
using namespace std;
  
void generatestring(int n)
{
    // Printing the character according to i
    for (int i = 0; i < n; i++)
        putchar(i & 2 ? 'b' : 'a');
    puts("");
}
  
// Driver code
int main()
{
    int n = 5;
    generatestring(n);
    n = 8;
    generatestring(n);
    n = 10;
    generatestring(n);
}

chevron_right


Java

filter_none

edit
close

play_arrow

link
brightness_4
code

// JAVA program find a binary String of 
// given length that doesn't contain
// a palindrome of size 3.
  
class GFG
{
  
static void generateString(int n)
{
    String s = "";
      
    // Printing the character according to i
    for (int i = 0; i < n; i++)
        s += ((i & 2) > 1 ? 'b' : 'a');
    System.out.println(s);
}
  
// Driver code
public static void main(String[] args)
{
    int n = 5;
    generateString(n);
    n = 8;
    generateString(n);
    n = 10;
    generateString(n);
}
}
  
// This code is contributed by Rajput-Ji

chevron_right


Output:


aabba
aabbaabb
aabbaabbaa


My Personal Notes arrow_drop_up


If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Improved By : Rajput-Ji



Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.