Question

Let's study the Palindrome number and Permutation today.
Palindrome is a phrase, number or sentence that reads the same either from start or end. A palindromic number is a number that remains the same when its digits are reversed. In other words, it has reflectional symmetry across a vertical axis. For example:- 1221, 1661, 5, 131. Permutation of N numbers is the arrangement of N different numbers from 1 to N. For example one of the possible permutation of 5 numbers is 3, 2, 4, 1, 5

Consider all palindromic numbers of even length (eg:- 11, 2332) where the first palindromic number of even length is 11. What will be the sum of digits of the Nth even palindromic number?​

Answer 1

Answer:

Input : n = "1" Output : 11 1st even-length palindrome is 11 . Input : n = "10" Output : 1001 The first 10 even-length palindrome numbers are 11, 22, 33, 44, 55, 66, 77, 88, 99 and 1001. As, it is a even-length palindrome so its first half should be equal to reverse of second half and length will be 2, 4, 6, 8 …