Apr 20

最近做SPOJ,发现很多题目的读入都是有大幅度优化余地的。事实上,在C++中,使用scanf()读入整数或者实数的速度都非常慢。我们可以通过一次读入一整行的来加快速度,方法是使用gets()。

对于gets()这个函数,GCC的文档建议不要使用。我个人的感觉是只要使用得当,这个函数还是大有用处的。比如下面的代码:

char buf[10000],*o;
inline int getint() {
  while (!isdigit(*o) && *o!='-') ++o;
  int r = 0,f = *o=='-'?++o,1:0;
  while (isdigit(*o)) r = r*10+*o++-'0';
  return (f?-r:r);
}

这个代码提供了一个getint()的函数来加快读入整数的速度。我们使用o = gets(buf),时候就可以进行相关的操作了。在这个函数的基础上稍作改进还可以读入实数等等。

Feb 6
(*O/*_/
Cu  #%* )pop mark/CuG 4 def/# 2 def%%%%@@P[TX---P\P_SXPY!Ex(mx2ex("SX!Ex4P)Ex=
CuG #%*                                                                  *+Ex=
CuG #%*------------------------------------------------------------------*+Ex=
CuG #%*   POLYGLOT - a program in seven languages      15 February 1991  *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*   Written by Kevin Bungard, Peter Lisle, and Chris Tham          *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*   We have successfully run this program using the following:     *+Ex=
CuG #%*     ANSI COBOL:            MicroFocus COBOL85 (not COBOL74)      *+Ex=
CuG #%*     ISO  Pascal:           Turbo Pascal (DOS & Mac), Unix PC,    *+Ex=
CuG #%*                            AIX VS Pascal                         *+Ex=
CuG #%*     ANSI Fortran:          Unix f77, AIX VS Fortran              *+Ex=
CuG #%*     ANSI C (lint free):    Microsoft C, Unix CC, GCC, Turbo C++, *+Ex=
CuG #%*                            Think C (Mac)                         *+Ex=
CuG #%*     PostScript:            GoScript, HP/Adobe cartridge,         *+Ex=
CuG #%*                            Apple LaserWriter                     *+Ex=
CuG #%*     Shell script:          gnu bash, sh (SysV, BSD, MKS), ksh    *+Ex=
CuG #%*     8086 machine language: MS-DOS 2.00, 3.03, 4.01, 5.00 beta    *+Ex=
CuG #%*                            VPix & DOS Merge (under unix)         *+Ex=
CuG #%*                            SoftPC (on a Mac), MKS shell          *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*   Usage:                                                         *+Ex=
CuG #%*     1. Rename this file to polyglot.[cob|pas|f77|c|ps|sh|com]    *+Ex=
CuG #%*     2. Compile and/or run with appropriate compiler and          *+Ex=
CuG #%*        operating system                                          *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*   Notes:                                                         *+Ex=
CuG #%*     1. We have attempted to use only standard language features. *+Ex=
CuG #%*        Without the -traditional flag gcc will issue a warning.   *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*     2. This text is a comment block in all seven languages.      *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*     3. When run as a .COM file with MS-DOS it makes certain      *+Ex=
CuG #%*        (not unreasonable) assumptions about the contents of      *+Ex=
CuG #%*        the registers.                                            *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*     4. When transfering From Unix to DOS make sure that a LF     *+Ex=
CuG #%*        is correctly translated into a CR/LF.                     *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*   Please mail any comments, corrections or additions to          *+Ex=
CuG #%*   peril@extro.ucc.su.oz.au                                       *+Ex=
CuG #%*                                                                  *+Ex=
CuG #%*------------------------------------------------------------------*QuZ=
CuG #%*                                                                  *+Ex=
CuG #%*!Mx)ExQX4ZPZ4SP5n#5X!)Ex+ExPQXH,B+ExP[-9Z-9Z)GA(W@'UTTER_XYZZY'CPK*+
CuG #(*                                                                  *(
C   # */);                                                              /*(
C   # *)  program        polyglot (output);                             (*+
C   #     identification division.
C   #     program-id.    polyglot.
C   #
C   #     data           division.
C   #     procedure      division.
C   #
C   # * ))cleartomark   /Bookman-Demi findfont 36 scalefont setfont     (
C   # *                                                                 (
C   #
C   # *                  hello polyglots$
C   #     main.
C   #         perform
C     * ) 2>_$$; echo   "hello polyglots"; rm _$$; exit
print
C             stop run.
-*,                'hello polyglots'
C
C         print.
C             display   "hello polyglots".                              (
C     */  int i;                                                        /*
C     */  main () {                                                     /*
C     */      i=printf ("hello polyglots\n"); O= &i; return *O;         /*
C     *)                                                                (*
C     *)  begin                                                         (*
C     *)      writeln  ('hello polyglots');                             (*
C     *)                                                                (* )
C     * ) pop 60 360                                                    (
C     * ) pop moveto    (hello polyglots) show                          (
C     * ) pop showpage                                                  ((
C     *)
end                                                          .(* )
C)pop%     program       polyglot.                                      *){*/}
Jan 31

比如,下面这几个可以输出自己的程序: 

class S{public static void main(String[]a){String s="class S{public static void main(String[]a){String s=;char c=34;System.out.println(s.substring(0,52)+c+s+c+s.substring(52));}}";char c=34;System.out.println(s.substring(0,52)+c+s+c+s.substring(52));}}
char*s="char*s=%c%s%c;main(){printf(s,34,s,34);}";main(){printf(s,34,s,34);}
#define q(k)main(){return!puts(#k"\nq("#k")");}
q(#define q(k)main(){return!puts(#k"\nq("#k")");})

还有用gcc编译输出C,g++编译输出C++的程序: 

#include <stdio.h>
int main() {
   putchar('C');
   #ifdef __cplusplus
   putchar('+'); putchar('+');
   #endif
   return 0;
}

下面的程序输出一个雪花曲线,看起来很像Java,但是却是C: 

/*
 * Sun's Java is often touted as being "portable", even though my code won't
 * suddenly become uber-portable if it's in Java. Truth is, Java's one of
 * the most ugly, slow, and straitjacketed languages ever. It's popular
 * mainly because people hear the word "portable" and go "ewww".
 *
 * This program, then, is dedicated to bringing about the death of Java. We
 * good coders have been oppressed for too long by the lame language
 * decisions of pointy-haired bosses and academics who should know better. 
 * It's time we stand up against this junk, and bring back the fun in
 * programming! Viva La Revolution!
 */

#define aSet c
#define BufferedReader(x)1
#define byte Y[I][_^1]?do(:):_&1?do(.):do(`):8;++y;}
#define class int N=0,_,O=328,l=192,y=4,Y[80][64]={0},I;struct
#define do(c)a(#c "\b")
#define err c,c
#define getAllStrings(x));q()
#define if(x)b(#x)
#define IOException
#define line c
#define main(a)b(char*x){write(1,"\033[",2),null}main()
#define new
#define null a(x);}a(char*x){write(1,x,strlen(x));try;try;try;try;
#define out c,c
#define println(x)c
#define private int d(int
#define public short c;}c;typedef int BufferedReader;char*F="JF>:>FB;;BII";
#define return {return
#define static f(x){N=(N+x)%6,y--?f(0),f(1),f(4),f(1):++Y[(I=O+N[F]-66)
#define String
#define System c
#define this if(D):1,O=I,I/=16,l<_/32?if(B):l>_/32?if(A):2,l=_,_/=16,byte
#define throws
#define toArray(x)c
#define try for(;--c.c;)
#define void /16][(_=l+N[6+F]-66)/16]?O/=16,l/=32,O<I/16?if(C):O>I/16?this
#define while(k)if(2J),if(7;21H),f(0),f(4),f(4),if(H),/*

import java.io.*;
import java.util.*;

/**
 * A lame Java program.
 * @author J. Random Worker
 */
class LameJavaApp
{

   /** The infamous Long-Winded Signature From Hell. */
   public static void main(String[] args)
     throws IOException
   {
     /* Don't get me started on this. */
     BufferedReader reader =
        new BufferedReader(new FileReader(args[0]));

     /* What, this long incantation just to print a string? */
       System.err.println("Hello world!");

     /* At least this is sane. */
     String line;
     while ((line = reader.readLine()) != null)
      System.out.println(line.length());
   }

   /**
    * Method with a needlessly long name.
    * @param aSet  a set (!)
    */
   private String[] getAllStrings(Set<String> aSet)
   {
     /*
      * This dance is needed even in J2SE 5, which has type
      * templates. It was worse before that.
      */
     return aSet.toArray(new String[0]);
   }

}