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reverse integer – leetcode a7

admin 11月 12, 2020 0

Problem

Problem description

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 hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Python “C-style” Implementation

class :
	def reverse(self, x):
		"""
		:type x: int
		:rtype: int
		"""
		sign = 1
		if (x < 0):
			sign = -1
			x = -x
		ans = 0
		while (x > 0):
			ans = ans * 10 + x % 10
			x = x // 10
			if ans*sign > ((1 << 31) - 1) or ans*sign < -(1 << 31):
				ans = 0
				break
		return ans*sign

Python Implementation

class :
	def reverse(self, x):
		"""
		:type x: int
		:rtype: int
		"""
		MaxInt = (1<<31)-1
		MinInt = -(1<<31)
		if x > 0:
			ans = int(str(x)[::-1])
		else:
			ans = int(str(-x)[::-1])*(-1)
		if (ans > MaxInt or ans < MinInt):
			ans = 0
		return ans