This content originally appeared on DEV Community and was authored by Simona Cancian
The problem is as follows:
Given an integer x, return true if x is a palindrome, and false otherwise.
Example 1:
Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.
Example 2:
Input: x = -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: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore, it is not a palindrome.
Here is how I solved it:
- Let's convert the given integer into a string
- In Python we can reverse a string by slicing: create a slice that starts at the end of the string and moves backwards. The slice statement
[::-1]means start and end of the string and end at position 0, move with the step-1, which means one step backwards. https://www.w3schools.com/python/python_howto_reverse_string.asp
rev = str(x)[::-1]
- Let's compare the reversed string to the given integer (again, convert it to string: we can only compare same datatypes). Return True if it matches, else False.
if rev == str(x):
return True
return False
But hey, we can actually write just one line of code using ternary operator! To be honest, I am not sure if it's bad design, but it seemed more readable to me.
Here is the complete solution:
class Solution:
def isPalindrome(self, x: int) -> bool:
return True if str(x)[::-1] == str(x) else False
This content originally appeared on DEV Community and was authored by Simona Cancian
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Simona Cancian | Sciencx (2024-07-03T02:19:12+00:00) Leetcode Day 2: Palindrome Number. Retrieved from https://www.scien.cx/2024/07/03/leetcode-day-2-palindrome-number/
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