Reverse the digits of an integer, keeping its sign. Leading zeros in the result are dropped (e.g. 120 → 21).
Input
A single integer (it may be negative).
Output
The integer with its digits reversed.
Reverse Integer
Easymath
Examples
Example 1
- Input
123
- Output
321
123 → 321.
Example 2
- Input
-45
- Output
-54
Sign kept: -45 → -54.
Example 3
- Input
120
- Output
21
Trailing zero becomes leading and is dropped: 120 → 21.
Constraints
- -10^15 <= n <= 10^15
Hints
Reveal hint 1
Handle the sign separately, then reverse the digit characters.
Reveal hint 2
Converting the reversed digit string back to an integer naturally drops leading zeros.
Reference solution (spoiler — try it yourself first)
Approach
Split off the sign, reverse the digit characters of the absolute value, parse back to an integer, and reapply the sign.
s = input().strip()
sign = -1 if s[0] == '-' else 1
digits = s.lstrip('-')
print(sign * int(digits[::-1]))
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