Leetcode-回文数(easy)

Problem description

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

Example 1:

Input: 121
Output: true

Example 2:

Input: -121
Output: false

Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:

Input: 10
Output: false

Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

Solution

成对比较头尾对应index的字符是否相等即可

class Solution:
    def isPalindrome(self, x: int) -> bool:
    if x<0:
             return False
        x = str(x)
        l = len(x)
        for i in range(0,int(l/2)):
            if x[i] is not x[l-i-1]:
                return False
        return True

不将整数转换成字符串的方法：
通过求余数的方法将整数进行反转，并将反转后的数字与原输入进行对比：

def isPalindrome(self, x: int) -> bool:
        if x<0:
            return False
        temp=x
        rev=0
        while(x>0):
            digit=x%10
            rev=rev*10+digit
            x=x//10
        if temp==rev:
            return True
        else:
            return False