Journal Archive

2022

/**
 * @param {string} s
 * @return {boolean}
 */
var isPalindrome = function(s) {
    let str = s.toLowerCase().replace(/[^a-z0-9]/g, "")
    let left = 0;
    let right = str.length - 1;
    while (left < right) {
        if (str[left] !== str[right]) return false;
        left++;
        right--;
    }
    
    return true;
};

Day 79: Solving one of LeetCode problems

125. Valid Palindrome Difficulty - Easy

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.