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'''
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判断一个整数是否是回文数。回文数是指正序（从左向右）和倒序（从右向左）读都是一样的整数。
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示例 1：输入: 121 输出: true
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示例 2：输入: -121 输出: false 解释: 从右向左读为 121- 。
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示例 3：输入: 10 输出: false 解释: 从右向左读为 01 。
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'''
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class Solution(object):
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def _isPalindrome(self, x): # 列表法，用两个指针，一个从前，一个从后判断是否相同
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"""
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:type x: int
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:rtype: bool
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"""
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str_x = list(str(x))
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i , j = 0 , len(str_x) - 1
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while i < j :
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if str_x[i] != str_x[j]:
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return False
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i += 1
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j -=1
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return True
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def isPalindrome(self, x: int): # 字符串法
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if x < 0:
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return False
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t=str(x)
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t =t[::-1] # 相当于t[-1:-len(t)-1:-1]，从最后一个元素到第一个元素复制一遍，即倒序
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t=int(t)
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if x==t:
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return True
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else :
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return False
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