两个大数据量处理的问题.被鄙视了呜呜

public class WordTree {
    
    public static void main(String[] args) {
        WordTree t = new WordTree();
        String[] ss = {"asdf", "asdf", "as", "a"};
        for(String s : ss) {
            t.accept(s);
        }
        CharNode cNode = t.getMaxNode();
        System.out.println(cNode.num + " : " + cNode.getS());
    }
    
    /**
     * 接收并处理一条新纪录
     * @author		lzxz
     * @param s		
     */
    public void accept(String s) {
        this.accept((CharSequence)s.toUpperCase());
    }
    
    /**
     * 得到最大数量节点
     * @author		lzxz
     * @return		
     */
    public CharNode getMaxNode() {
        int maxNum = 0;
        CharNode maxNode = null;
        for(CharNode cNode : list) {
            if(cNode.num > maxNum) {
                maxNode = cNode;
                maxNum = cNode.num;
            }
        }
        return maxNode;
    }
    
    /**
     * 得到最大数量节点，要求必须全部大写
     * @author		lzxz
     * @param cs		
     */
    public void accept(CharSequence cs){
        this.root.accept(cs);
    }
    
    private CharNode root = new CharNode(null, '$');
    private final List<CharNode> list = new ArrayList<CharNode>();
    
    private class CharNode {
        private char c;
        private int num;
        private CharNode parent = null;
        
        private Map<Character, CharNode> next;
        
        /**
         * 得到到达本路径的字符串全量
         * @author		lzxz
         * @return		
         */
        private String getS() {
            if(this.parent == null) {
                return String.valueOf(c);
            }
            
            return this.parent.getS() + c;
        }
        /**
         * 接收并处理一条新纪录
         * @author		lzxz
         * @param cs		
         */
        private void accept(CharSequence cs) {
            CharNode node = next.get(cs.charAt(0));
            if(node == null) {
                node = new CharNode(this, cs.charAt(0));
                next.put(cs.charAt(0), node);
                list.add(node);
            }
            
            if(cs.length() == 1){
                node.num ++;
            } else {
                node.accept(cs.subSequence(1, cs.length()));
            }
        }
        
        /**  
         * 指定参数构造CharNode实例。
         * @param parent
         * @param c   
         */
        public CharNode(CharNode parent, char c){
            num = 0;
            this.parent = parent;
            this.c = c;
            next = new HashMap<Character, CharNode>();
        }
    }
}