hdu 4825 Xor Sum 位操作 字典树

遇到本题，在对象成员中申请数组空间的话，会不明就里地TLE，而且浪费大量内存。

/**
 * 2015年7月15日 上午11:21:15
 * PrjName:hdu4825
 * @ Semprathlon
 */

import java.io.*;

class Trie {
    private final int maxd = 33;
    private long data;
    private Trie ch0, ch1;

    void insert(long n) {
        Trie rt = this;
        for (int i = maxd - 1; i >= 0; i--) {
            if ((n & (1L << i)) == 0L) {// 0
                if (rt.ch0 == null)
                    rt.ch0 = new Trie();
                rt = rt.ch0;
            } else {// 1
                if (rt.ch1 == null)
                    rt.ch1 = new Trie();
                rt = rt.ch1;
            }
            if (i == 0)
                rt.data = n;
        }
    }

    long query(long n) {
        Trie rt = this;
        for (int i = maxd - 1; i >= 0; i--) {
            if ((n & (1L << i)) > 0L && rt.ch0 != null || rt.ch1 == null)// 0
                rt = rt.ch0;
            else if (rt.ch1 != null)// 1
                rt = rt.ch1;
        }
        return rt.data;
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        StreamTokenizer in = new StreamTokenizer(new BufferedReader(
                new InputStreamReader(System.in)));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        int cas = 0;
        in.nextToken();
        int T = (int) in.nval;
        while (T-- > 0) {
            Trie tr = new Trie();
            in.nextToken();
            int n = (int) in.nval;
            in.nextToken();
            int m = (int) in.nval;
            for (int i = 1; i <= n; i++) {
                in.nextToken();
                tr.insert((long) in.nval);
            }
            out.println("Case #" + (++cas) + ":");
            for (int i = 1; i <= m; i++) {
                in.nextToken();
                out.println(tr.query((long) in.nval));
            }
        }
        out.flush();
        out.close();
    }

}