ACM常用的Java代码

 import java.util.*;
 import java.io.*;
 
 public class Main {
     public static void main(String[] args) throws IOException{
         // 计算程序运行时间
         // Arrays
         long st = System.currentTimeMillis();
         if ("abc" == "abc") System.out.println("Yes1");
         String str1 = new String("abc");
         String str2 = new String("abc");
         if (str1 == str2) System.out.println("Yes2");
         if (str1.equals(str2)) System.out.println("Yes3");
 
         //
         int[] t = {5, 1, 3, 2, 9};
         Arrays.sort(t);
         System.out.println(Arrays.toString(t));
         int[] s = new int[10];
         Arrays.fill(s, 33);
         System.out.println(Arrays.toString(s));
         // returns ((-insertion point) - 1) if key not exists.
         System.out.println(Arrays.binarySearch(t, 4));
         int cnt = 0;
         for (int i = 1; i < 100000000; i++) {cnt++;}
         long ed = System.currentTimeMillis();
         System.out.println("time: " + (ed - st));
 
         // 字符串hash
         String str = new String("hello world");
         System.out.println("hash Code: " + str.hashCode());
 
         // BufferReader缓冲与换行读取功能
         BufferedReader cin = new BufferedReader(new InputStreamReader(System.in));
         int sum = 0;
         String ss = null;
         while ((ss = cin.readLine()) != null) {
             sum += Integer.parseInt(ss);
         }
         System.out.println("the sum is: " + sum);
 
         //
 
     }
 }