[leetcode]Valid Palindrom

上一段神code

1 2	s=s.toLowerCase().replaceAll("[^a-z0-9]", ""); return new StringBuilder(s).reverse().toString().equals(s);

简练！

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public class Solution { public boolean isPalindrome(String s) { int left = 0; int right = s.length()-1; while (left < right){ char leftC = Character.toLowerCase(s.charAt(left)); char rightC = Character.toLowerCase(s.charAt(right)); boolean leftValid = validCheck(leftC); boolean rightValid = validCheck(rightC); if(!leftValid){ left++; } if(!rightValid){ right--; } if (leftValid && rightValid){ if (leftC != rightC) return false; left++; right--; } } return true; } boolean validCheck(char a){ return Character.isAlphabetic(a) || Character.isDigit(a); } }