Given an integer N, the task is to print first Nth pure numbers. A number is said to be pure if
- It has even number of digits.
- All the digits are either 4 or 5.
- And the number is a palindrome.
First few pure numbers are 44, 55, 4444, 4554, 5445, 5555, …
Input: N = 4
Output: 44 55 4444 5445
Input: N = 10
Output: 44 55 4444 4554 5445 5555 444444 454454 544445 554455
Approach: The idea is similar to the approach discussed here. At each step of the queue we can generate the next number by adding 4 and 5 on both of the sides i.e. the ending and the beginning of the previous number:
q.push("4" + temp + "4"); q.push("5" + temp + "5");
Proceeding in this way we can take care of palindromes and even length numbers
Below is the implementation of the above approach:
44 55 4444 5445
- Find original numbers from gcd() every pair
- Find first k natural numbers missing in given array
- Find the k largest numbers after deleting the given elements
- Rearrange numbers in an array such that no two adjacent numbers are same
- Sort all even numbers in ascending order and then sort all odd numbers in descending order
- Segregate even and odd numbers | Set 3
- Sort 3 numbers
- Stepping Numbers
- Kth number from the set of multiples of numbers A, B and C
- Sort the numbers according to their sum of digits
- Sum of Semi-Prime Numbers less than or equal to N
- No of pairs (a[j] >= a[i]) with k numbers in range (a[i], a[j]) that are divisible by x
- Sort the numbers according to their product of digits
- Making three numbers equal with the given operations
- Sort an array of large numbers
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. 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.