Java快速IO(ACM)必備

摘要： en.... 無非用到的是 1. new Scanner(System.in); 2.new BUfferReader(new InputStreamReader(System.in); 3.System.in.read() //需要轉換 當然1，2這兩個還有許多坑要注意，...

en....

無非用到的是

1. new Scanner(System.in);

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

3.System.in.read() //需要轉換

當然1，2這兩個還有許多坑要注意，比如說 next() 不會讀入null字元，就一直等待，nextline() 吸收\n到緩衝區 但是不會讀入，readLine 與read（）也是一樣

這裡需要注意：in.nextInt() 接著 in.nextLine（）會出現讀入空缺現象，很明顯，我前面說過，nextLine會吸收\n到緩衝區

貼程式碼：

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解決超時 {
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());
}
}