/**125. Valid Palindrome
* @param s
* @returnboolean
*/
public boolean isPalindrome(String s) {
if (s == null || s.length() <= 1)
return true;
for (int i=0, j=s.length()-1; i<=j; ) {
char ch1 = s.charAt(i);
char ch2 = s.charAt(j);
if (isValidChar(ch1) && isValidChar(ch2)) {
if(Character.toLowerCase(ch1) == Character.toLowerCase(ch2)) {
i++;
j--;
} else {
return false;
}
} else if (!isValidChar(ch1)){
i++;
} else if (!isValidChar(ch2)) {
j--;
}
}
return true;
}
public boolean isValidChar(char ch1) {
if ((ch1 >= 'a' && ch1 <= 'z') || (ch1 >= 'A' && ch1 <= 'Z') || (ch1 >= '0' && ch1 <= '9'))
return true;
return false;
两头依次向里走,边走变比较
Character.toLowerCase(ch)