Q: A number is given as a palindrome, write a function to return the next largest palindrome.

Algorithm:

Case I: The given number is a palindrome..ex: 1234321 then simply increment the centre digit by 1 i.e the answer is 1235321

Case II: The given number is not a palindrome:

Subcase 1: The number to the left of the middle digit is greater than the number on the right ex:2194135 (here 219 > 135) then,reverse the left side numbers and replace the right side numbers with them, therefore the answer will be 2194912.

Subcase 2:The number to the right of the middle digit is greater than the number on the left ex:1354219 then,

then increment the middle digit by 1 and then reverse the left side numbers and replace the right side numbers with them. Therefore the answer would be 135 5(middle digit incremented) 531(reversed), resulting in 1355531, which is the next palindrome.

Note: in case the middle digit is 9 then incrementing it would make it 10, so put 0 instead of 9 and increment the first right and left neighbouring digit of 9 by 1.

## 1 comment:

You have not considered the cases where the no. of digits are even!!

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