Java快速IO(ACM)必备

 en....

无非用到的是

1. new Scanner(System.in);

2.new BUfferReader(new InputStreamReader(System.in);

3.System.in.read() //需要转换

当然1，2这两个还有许多坑要注意，比如说 next() 不会读入null字符，就一直等待，nextline() 吸收\n到缓冲区 但是不会读入，readLine 与read（）也是一样

这里需要注意：in.nextInt() 接着 in.nextLine（）会出现读入空缺现象，很明显，我前面说过，nextLine会吸收\n到缓冲区

贴代码：

package IO;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

/**
 * Class for buffered reading int and double values
 */
class Reader解决超时 {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /**
     * call this method to initialize reader for InputStream
     */
    static void init(InputStream input) {
        reader = new BufferedReader(
                new InputStreamReader(input));
        tokenizer = new StringTokenizer("");
    }

    /**
     * get next word
     */
    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                    reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static String nextLine()throws IOException{
        while(!tokenizer.hasMoreElements()){
            tokenizer=new StringTokenizer(
                    reader.readLine()
            );
        }
        return tokenizer.nextToken("\n");
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    public static void main(String[] args) throws IOException{
        init(System.in);
        StringTokenizer st = new StringTokenizer("this is a test");

        while (st.hasMoreTokens())

        {

            System.out.println(st.nextToken());

        }
       // System.out.println(next());
        System.out.println(nextLine());
    }
}