LeetCode/com/zerroi/leetcode/ThreeTen/IsPalindrome.java

package com.zerroi.leetcode.ThreeTen;


public class IsPalindrome {
    public static void main(String[] args) {
        SolutionSecond solutionSecond = new SolutionSecond();
        solutionSecond.isPalindrome("race a car");
    }
}

class SolutionSecond {
    public boolean isPalindrome(String s) {
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if ((c >= 65 && c <= 90) || (c >= 97 && c <= 122) || (c >= 48 && c <= 59)) {
                builder.append(String.valueOf(c).toLowerCase());
            }
        }
        String str = builder.toString();
        return builder.reverse().toString().equals(str);
    }

    public boolean isPalindromeTow(String s) {

        class Solution {
            public boolean isPalindrome(String s) {
                boolean ans = true;
                int l = 0;
                int r = s.length() - 1;
                while (true) {
                    if (l > r) {
                        break;
                    }
                    char lc = s.charAt(l);
                    char rc = s.charAt(r);
                    if (!Character.isLetterOrDigit(lc)) {
                        l++;
                        continue;
                    }
                    if (!Character.isLetterOrDigit(rc)) {
                        r--;
                        continue;
                    }
                    if (Character.toLowerCase(lc) == Character.toLowerCase(rc)) {
                        l++;
                        r--;
                    } else {
                        ans = false;
                        break;
                    }
                }
                return ans;
            }
        }
        return false;
    }
}