[Thoughts]
pseudo code: (with two examples in parentheses)
- Convert the number into string. (1224, 39999)
- take half of the string. ( "12", "399" )
- copy first half to second half in reverse order (take care of no of chars)
( "12" -> "1221", "399" -> "39993" )
- convert to number and measure the abs. difference with original number - diff1
( |1221 - 1224| = 3, |39993-39999| = 6)
- add 1 to half string and now copy first half to second half in reverse order
( 12+1 = 13, 399 + 1 = 400, 13-> 1331, 400->40004)
- convert to number and measure the abs. difference with original number - diff2
( |1331-1224| = 107, |40004-39999| = 5 )
- if diff1<diff2 return first number else return second number
( 1221, 40004)