LEETCODEEasy
Valid Palindrome
A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
Given a string s, return true if it is a palindrome, or false otherwise.
Example 1:
Input: s = "A man, a plan, a canal: Panama" Output: true Explanation: "amanaplanacanalpanama" is a palindrome.
Example 2:
Input: s = "race a car" Output: false Explanation: "raceacar" is not a palindrome.
Example 3:
Input: s = " " Output: true Explanation: s is an empty string "" after removing non-alphanumeric characters. Since an empty string reads the same forward and backward, it is a palindrome.
Constraints:
1 <= s.length <= 2 * 105sconsists only of printable ASCII characters.
풀이 TypeScript
function isPalindrome(s: string): boolean {
const convertedString = s.toLowerCase().replace(/[^a-z0-9]/g, '');
const length = convertedString.length
const halfLength = Math.floor((length - 1) / 2);
for(let i = 0; i <= halfLength; i++) {
const first = convertedString[i]
const last = convertedString[length - i - 1]
if(first !== last) return false
}
return true;
}복사됨