Given a 32-bit signed integer, reverse digits of an integer.
Example 1:
Input: 123
Output: 321
Example 2:
Input: -123
Output: -321
Example 3:
Input: 120
Output: 21
Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
class Solution(object):
def reverse(self, x):
"""
:type x: int
:rtype: int
"""
overflow_pos=pow(2,31)-1
overflow_neg=float(-pow(2,31))
rev=0
while x!=0:
trunc=int(float(x)/10)
pop=x-trunc*10
x=trunc
if rev > overflow_pos/10 or (rev==overflow_pos//10 and pop > 7): return 0
if rev < overflow_neg/10 or (rev==int(overflow_neg/10) and pop < -8): return 0
rev=rev*10+pop
return rev