Leetcode检测时是对的但是一执行就错，我放在myeclipse里面也是对的

Question

Answer 1

class Solution {
	public boolean isPalindrome(String s) {

		s = s.toLowerCase();
		String p = "";
		for (int i = 0; i < s.length(); i++) {
			if ((s.charAt(i) >= 'a' && s.charAt(i) <= 'z') || (s.charAt(i) >= '0' && s.charAt(i) <= '9')) {
				p = p + s.substring(i, i + 1);

			}

		}

		for (int i = 0; i < p.length()/2; i++) {
			if (p.charAt(i) != p.charAt(p.length() - i - 1)) {
				return false;
			}
		}
		return true;

	}
}