Algorithms to solve programming contest problems

[rst256 via Digitalmars-d]

On Saturday, 25 October 2014 at 20:51:04 UTC, Walter Bright wrote:
> http://www.quora.com/What-are-the-algorithms-required-to-solve-all-problems-using-C++-in-any-competitive-coding-contest
>
> Anyone want to review these and see what we should add to 
> Phobos?

Dear Mr. Bright.

Just can not now comment. Please see this code. test code and 
profililing log.

src\phobos\std\stdio.d: lines 361-373 
-------------------------------
  */                      /*file and line in this is demo solve. 
Just for profilling. I now more safety way. */
     this(string name, in char[] stdioOpenmode = "rb", string file 
= __FILE__, size_t line = __LINE__) @safe
     {
         import std.conv : text;
         import std.exception : ErrnoException;

         /*this(errnoEnforce(.fopen(name, stdioOpenmode),
                         text("Cannot open file `", name, "' in 
mode `",
                                 stdioOpenmode, "'")),
                 name); */
		if (!.fopen(name, stdioOpenmode)) throw new 
ErrnoException(text("Cannot open file `", name, "' in mode `",
                                 stdioOpenmode, "'"), file, line);
     }

file.d(test 
code)-----------------------------------------------------------

import std.stdio;

void main(string[] args)
{
		/*int i;
		int a[2];
		if(true) i = 3;
		a[i] = 3;*/
		auto fobj = File("hello2.d");
		scope(failure) writefln("scope(failure)");
		scope(exit) writefln("scope(exit)");
		writefln("end");
}

profiler log for file.d with old version 
phobos----------------------
------------------
	    1	_Dmain
	    7	main
_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa	8	89	80
	    8	_D6object19__T11_doPostblitTaZ11_doPostblitFNaNbNiAaZv
------------------
	    8	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa
_D6object19__T11_doPostblitTaZ11_doPostblitFNaNbNiAaZv	8	9	9
------------------
	    1	main
_Dmain	1	40831907	40831897
	    1	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa
------------------
main	0	0	0
	    1	_Dmain
	    7	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa

======== Timer Is 3579545 Ticks/Sec, Times are in Microsecs 
========

   Num          Tree        Func        Per
   Calls        Time        Time        Call

       1    11407010    11407007    11407007     _Dmain
       8          24          22           2     pure nothrow 
char[] object._dup!(const(char), char)._dup(const(char)[])
       8           2           2           0     pure nothrow 
@nogc void object._doPostblit!(char)._doPostblit(char[])
       1           0           0           0     main

new version-------------------------------------------
------------------
	    1	_Dmain
	    7	main
_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa	8	102	88
	    8	_D6object19__T11_doPostblitTaZ11_doPostblitFNaNbNiAaZv
------------------
	    8	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa
_D6object19__T11_doPostblitTaZ11_doPostblitFNaNbNiAaZv	8	14	14
------------------
	    1	main
_Dmain	1	2336665	2336654
	    1	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa
------------------
main	0	0	0
	    1	_Dmain
	    7	_D6object14__T4_dupTxaTaZ4_dupFNaNbAxaZAa

======== Timer Is 3579545 Ticks/Sec, Times are in Microsecs 
========

   Num          Tree        Func        Per
   Calls        Time        Time        Call

       1      652782      652779      652779     _Dmain
       8          28          24           3     pure nothrow 
char[] object._dup!(const(char), char)._dup(const(char)[])
       8           3           3           0     pure nothrow 
@nogc void object._doPostblit!(char)._doPostblit(char[])
       1           0           0           0     main

I not check the other functions, because not sure that this style 
of coding is enough object oriented. It object only because  that 
here you have objects.
if you need it, let's work.
Best regards.