11070 - The Good Old Times

All about problems in Volume 110. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

Moderator: Board moderators

shanto86
Experienced poster
Posts: 160
Joined: Wed Jul 30, 2003 8:10 pm

Post by shanto86 » Fri Aug 18, 2006 8:10 pm

What about

Code: Select all

-9/-3 - 3
-9/-3 + 3
-9/-3+-3
-9/+3-+3
Self judging is the best judging!

Tosgin
New poster
Posts: 2
Joined: Wed May 31, 2006 4:47 pm
Location: Bosnia and Herzegovina, Sarajevo

Post by Tosgin » Fri Aug 18, 2006 8:35 pm

Your first two test cases are invalid because they contain blanks.
Qute from the problem statement:
Because main memory was very small in those days, the string will contain no blanks or tabs, nor parathensis.

shanto86
Experienced poster
Posts: 160
Joined: Wed Jul 30, 2003 8:10 pm

Post by shanto86 » Fri Aug 18, 2006 8:44 pm

well... actually just omit the blanks. i did not want to give blank. it was a mistake!
Self judging is the best judging!

User avatar
little joey
Guru
Posts: 1080
Joined: Thu Dec 19, 2002 7:37 pm

Post by little joey » Fri Aug 18, 2006 9:34 pm

Just some randomly generated input:

Code: Select all

-30.886/-47.793*-60.492--2.362*-20.059*80.540+-55.736+-2.567*21.530
-74.067-79.802*-33.069--18.456*-76.229-44.919-75.198/-64.370*76.091+41.873*-6.996-20.925/-60.336*-21.729--16.124*0.545/15.434/-13.750+17.276+-93.584/-92.754+95.060+47.739*98.586
40.795*-60.378-10.097-70.492+97.301*-9.441--28.444+-44.729--38.097--90.675/4.567-72.353--55.306/28.624/-5.732
30.019+-59.708+18.149/-42.618
-93.451/92.379+-88.228*65.193*87.764*36.987/-46.491-9.859+-52.551+-53.275*76.121/-36.029/73.793+-66.143+39.529+-64.443-54.538+2.904+-70.688-69.917+87.743/-98.490
6.725*-17.505*-69.786*8.542--39.507+-76.348*-27.828/95.746+-55.422*-67.605-73.730-29.320+48.626-86.708*13.258-42.062+32.036/19.379+-90.071/3.881-45.894/-57.199/-52.996
72.813*81.095*65.084*27.684*-55.936--19.756*6.887+-32.172-2.336*67.587-97.713--1.255/17.721/39.811/11.705/29.150*63.920*67.269-45.630+11.972*-47.625*39.299*-83.898*56.190
-88.209/99.336/95.994/-14.769+-68.850+-48.142+-21.993-79.567-1.961*54.259*13.202+2.021+-89.528+49.908*48.036--86.248
32.133*-99.754*-90.368+38.046-66.249/-3.033-10.253*19.125+45.975
3.729+-53.414+26.304/78.050+8.902--58.699/32.002/-44.500
-8.538/22.535/-71.692/-20.504--90.964--95.343-2.900/-16.949/17.988/40.743-58.390+-53.541*-74.232*-90.360/-66.761--3.190+-6.367*30.690+26.057+28.205+47.386*2.726+56.552
28.946/-56.970+-99.631-18.627*-39.214
20.090/-9.610--52.274--56.620/77.888*87.770+90.417+-25.849--73.059*-34.945--28.458--4.289/-70.478
-34.471+33.459*58.025*-31.233-3.493*-10.699/-75.569*-28.794/96.431*39.390/-5.057-96.157/-1.947/-35.021+85.054
-35.325+53.516/46.139+82.338*39.021*-84.812-92.685+-24.176/-99.759+-93.499/63.950+-67.818/40.049/41.805/-77.375*33.589--44.918*44.822--24.030*-30.126*-50.253*-27.814/38.377/-27.088
6.732--0.346--45.691/22.573-49.291*77.217/75.055*78.130/-72.661--4.789+-56.851
-67.868
-39.006/62.949/-80.226--90.596-87.560/67.770/66.342+-72.379*94.984/44.234/70.072
-1.063*-82.030*86.059/26.924/71.232*30.443
75.640/50.262/61.041/8.324*-54.154--37.457/91.171--25.218/-14.653/53.959*15.797+21.308
And its output:

Code: Select all

-3966.030
5721.216
-3493.352
-30.115
401263.465
72715.847
-489478929.616
772.852
289574.936
-40.487
5555.057
630.300
-2346.095
-60589.550
-269634.795
11.568
-67.868
88.366
119.117
21.055

ivan.cu
New poster
Posts: 21
Joined: Sun Mar 19, 2006 7:50 pm
Location: Cuba

I got AC!!

Post by ivan.cu » Fri Aug 18, 2006 11:35 pm

After ages i got AC, the problem is floating point error, first in my Java program and next in C++ program for use float instead of double. for read double use the format "%lf" in function scanf or sscanf.

Thank to all for your help.

User avatar
Zaspire
New poster
Posts: 36
Joined: Sun Apr 23, 2006 2:42 pm
Location: Russia

Help please

Post by Zaspire » Sat Aug 19, 2006 1:08 pm

I get WA many times. Why? Help please!

Code: Select all

#include <stdio.h>
#include <math.h>

double work(char *t1,int size)
{
	if (*t1=='+') return work(t1+1,size-1);
	double res=0;
	for (int i=size-1;i>0;i--)
	{
		if (t1[i]=='+'||t1[i]=='-')
			if (t1[i-1]!='/'&&t1[i-1]!='*')
			{
				res=work(t1,i);
				if (t1[i]=='+') res+=work(t1+i+1,size-i-1);
				else res-=work(t1+i+1,size-i-1);
				return res;
			}
	}
	for (int i=size-1;i>-1;i--)
	{
		if (t1[i]=='/'||t1[i]=='*')
		{
			res=work(t1,i);
			if (t1[i]=='/') res/=work(t1+i+1,size-i-1);
			else res*=work(t1+i+1,size-i-1);
			return res;
		}
	}
	sscanf(t1,"%lf",&res);
	return res;
}

int main()
{
#ifndef ONLINE_JUDGE
	//freopen("in.txt","r",stdin);
#endif
	char str[270],*t1,c,last;
	int size;
	double res;
	do
	{
		do
		{
			c=getchar();
		}
		while (c!=EOF&&(c<'0'||c>'9')&&c!='-'&&c!='+');
		t1=str;
		size=0;
		last='/';
		while (c!='\n'&&c!=EOF)
		{
			if (last=='/'||last=='*')
			{
				if (c=='-'||(c>='0'&&c<='9')) {*t1=last=c;t1++;size++;}
			}
			else
				if (last=='+'||last=='-')
				{
					if (c=='-') 
						if (last=='-') *(t1-1)=last='+';
						else *(t1-1)=last='-';
					else
						if (c=='+')
							if (last=='-') *(t1-1)=last='-';
							else *(t1-1)=last='+';
						else
						{
							*t1=last=c;
							t1++;
							size++;
						}
				}
				else
				{
					*t1=last=c;
					t1++;
					size++;
				}
			c=getchar();
		}
		*t1='\0';
		if (size)
		{
			res=work(str,size);
			if (abs(res)<0.0001) printf("0.000\n");
			else printf("%.3lf\n",res);
		}
	}while (c!=EOF);
	return 0;
}

User avatar
Sedefcho
A great helper
Posts: 374
Joined: Sun Jan 16, 2005 10:18 pm
Location: Bulgaria

Post by Sedefcho » Sat Aug 19, 2006 8:42 pm

Thanks for the input, little joey.

The first answer of my prog for your test cases was:
-3966.-29
( That's because I have a stupid custom Java method which
rounds doubles up to three digits after the decimal point,
and that method was not working for negative numbers at all ).

Which explains the WA which I was getting...

Regards.

User avatar
Martin Macko
A great helper
Posts: 481
Joined: Sun Jun 19, 2005 1:18 am
Location: European Union (Slovak Republic)

Re: Help please

Post by Martin Macko » Wed Aug 23, 2006 9:18 pm

Zaspire wrote:I get WA many times. Why? Help please!
I don't know how the floating point numbers in the input file may or may not be written, but your solution isn't working well for numbers such as .5:

Code: Select all

1/.5
The correct output:

Code: Select all

2

Darko
Guru
Posts: 580
Joined: Fri Nov 11, 2005 9:34 am
Location: Calgary, Canada

Post by Darko » Wed Aug 23, 2006 9:23 pm

My AC code produces:

Code: Select all

-0.067
I assumed that numbers start with digits and used do-while instead of while.

User avatar
Zaspire
New poster
Posts: 36
Joined: Sun Apr 23, 2006 2:42 pm
Location: Russia

Post by Zaspire » Mon Aug 28, 2006 10:01 am

I corect my program and it's work with 1/.5 but still get WA.
After that I simple remove line :P

Code: Select all

if (abs(res)<0.0001) printf("0.000\n");
A get AC. But Why :o ?
if abs(res)<0.0001 the output must be 0.000, But it's wrong?

helloneo
Guru
Posts: 516
Joined: Mon Jul 04, 2005 6:30 am
Location: Seoul, Korea

Post by helloneo » Mon Aug 28, 2006 2:51 pm

Zaspire wrote:I corect my program and it's work with 1/.5 but still get WA.
After that I simple remove line :P

Code: Select all

if (abs(res)<0.0001) printf("0.000\n");
A get AC. But Why :o ?
if abs(res)<0.0001 the output must be 0.000, But it's wrong?
abs() is for integers.. you may use fabs() instread

User avatar
Martin Macko
A great helper
Posts: 481
Joined: Sun Jun 19, 2005 1:18 am
Location: European Union (Slovak Republic)

Post by Martin Macko » Tue Aug 29, 2006 10:38 pm

helloneo wrote:abs() is for integers.. you may use fabs() instread
It depends. In plain C abs() is for integers only, however in C++ abs() is an overloaded symbol for:
  • - double abs(double __x);
    - float abs(float __x);
    - long double abs(long double __x);
defined in <cmath> and for:
  • - long abs(long __i);
    - long long abs(long long __x);
defined in <cstdlib>. Therefore, if you write the following in C++, you get the correct answer (i.e., 4.700).
  • #include <cmath>

    int main()
    {
    • ...
      double a=-4.7;
      printf("%3lf\n", abs(a));
      ...
    }

Shafaet_du
Experienced poster
Posts: 147
Joined: Mon Jun 07, 2010 11:43 am
Location: University Of Dhaka,Bangladesh
Contact:

Re: 11070 - The Good Old Times

Post by Shafaet_du » Fri Apr 29, 2011 9:43 pm

Can anyone tell me why C++ shows -0.000 in case like -10*0 ?? Does that make any sense? I wrote this way to avoid the trap:

Code: Select all

if(STK[0]<1e-11 && STK[0]>-(1e-11)) STK[0]=0;
        printf("%.3lf\n",STK[0]);

Post Reply

Return to “Volume 110 (11000-11099)”