public boolean isPalindrome(String s) {
    	char[] cs = new char[100000];
    	int idx = 0;
        for( char c : s.toLowerCase().toCharArray()){
        	if((c >= 'a' && c <= 'z') || (c >='0' && c <= '9')) cs[idx++] = c;
        }
        for(int i = 0; i<idx; i++){
        	int j = idx - (i+1) ;
        	if(i>j) return true;
        	else{
        		if(cs[i] != cs[j]) return false;
        	}
        }
        return true;
        
    }