What is the measning of this question?

#1

what is the measning of this question???

#2

In this question you have to find and print the smallest number possible by reversing digits of the input.

  • As x <= 100000000000000000, use long long int datatype or for this specific question, you can use a string also as it is easier to iterate on digit of the number.

  • Now starting from the leftmost digit in the number iterate till the rightmost digit, do the following:
    2.1. find the invert of the current digit s[i] i.e. 9-s[i]
    2.2. check if the invert is smaller than the actual digit:
    …if yes, then replace the digits[i] in the number with it’s invert.
    …if no, then don’t replace
    example 1:
    123
    inverting 1: 9-1=8
    as 8>1,
    so, if i would replace 1 with 8 (i,e 823), then the number will become larger.
    But, we are required to find the smallest, so don’t replace.
    example 2:
    632
    inverting 6: 9-6=3
    as 3<6,
    so, if i would replace 6 with 3 (i,e 332), then the number will become smaller.
    Thus, replace will be made.

  • As it is mentioned that the leftmost digit can’t be 0, so we would not replace if a[0]=9
    example:
    912
    inverting 9: 9-9=0
    0<9,
    But, the number cannot start with 0.
    So, we won’t replace.

Hope, this would help.

#3

what does revert means and 9-n

#4

You have to invert the digits in order to form the minimum possible number. Inverting a digit here means replacing that digit with (9-original digit)