Description
https://leetcode.com/problems/valid-palindrome/
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
Note: For the purpose of this problem, we define empty string as valid palindrome.
Example 1:
Input: "A man, a plan, a canal: Panama" Output: true
Example 2:
Input: "race a car" Output: false
Explanation
A palindrome, and its reverse, are identical to each other.
Python Solution
class Solution:
def isPalindrome(self, s: str) -> bool:
i = 0
j = len(s) - 1
s = s.lower()
left = ""
right = ""
for i in range(0, len(s)):
if s[i].isalpha() or s[i].isdigit():
left += s[i]
for j in range(len(s) - 1, -1, -1):
if s[j].isalpha() or s[j].isdigit():
right += s[j]
return left == right- Time complexity: O(N).
- Space complexity: O(N).
Hi! I’ve posted my solution below. Could you tell me why for some cases I get an index out of bounds exception?
class Solution {
public boolean isPalindrome(String s) {
char[] arr = s.toCharArray();
int end = s.length() – 1;
for(int start = 0; start
= s.length()) {return false;
}
start++;
}
while(isLetter(arr[end]) == false) {
if(end = ‘a’ && c = ‘A’ && c <= 'Z') {
return true;
}
return false;
}
}