Coding Challenge Of The Day

[Chris Losinger]

for well-formed roman numerals, modern rules:

int r2d2(const char *r)
{
int val[128];
memset(val,0,sizeof(int)*128);
val['I']=1; val['V']=5;
val['X']=10; val['L']=50;
val['C']=100; val['D']=500; val['M']=1000;

int a = 0;
for (int cv, pv = 0, i=strlen(r)-1;i>=0;i--)
{
cv = val[r[i]];
a += cv * (pv > cv ? -1 : 1);
pv = cv;
}

return a;

}

image processing toolkits | batch image processing

[AspDotNetDev]

Chris Maunder wrote:

obfuscated assembler

Tautology.

Thou mewling ill-breeding pignut!

[Chris Meech]

I once met a well formed roman, when I was touring through Italy. :cool:

Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]

[Bassam Abdul Baki]

In URL form: http://en.wikipedia.org/wiki/Roman_numerals#External_links[^] :-D Another interesting fact: http://answers.yahoo.com/question/index?qid=20100525032737AATfpBJ[^]

Web - BM - RSS - Math - LinkedIn

[Joan M]

Chris... you should know that we don't make homework here... :rolleyes:

[www.tamautomation.com] Robots, CNC and PLC machines for grinding and polishing.

[wizardzz]

I never enter a contest without knowing the prize, for tax purposes, but also in this case, it could be a job at CP... :doh:

[wizardzz]

I didn't see you award him any points. Go on, 5 him!

[Chris Maunder]

Actually it's a personality test to see who among you are worthy of being labelled a Brogrammer.

cheers, Chris Maunder The Code Project | Co-founder Microsoft C++ MVP

[S Houghtelin]

Thanks wizardzz, I suppose he meant like virtual points, or maybe pints, I'll definitely takes pints! :-D

It was broke, so I fixed it.

[Steve Mayfield]

Don't you mean 'V' him?

Steve _________________ I C(++) therefore I am

[Bassam Abdul Baki]

You may want to snag CodeBroject.com just in case (CodePreject.com too).

Web - BM - RSS - Math - LinkedIn

[S Houghtelin]

Just like positive reenforcment in the schools today, everybody gets a trophy, even when they're wrong. Thanks! :thumbsup: :-D

It was broke, so I fixed it.

[Sentenryu]

as a nerd, i can't resist... between, it's only a quick n' dirty solution:

public static int RomanToArabic(string romans) {
if (string.IsNullOrWhiteSpace(romans))
{
return 0;
}
//remove whitespace...
romans = romans.Replace(" ", string.Empty);
//make sure no one pass out an "A" for example...
if (!Regex.IsMatch(romans, "(I|V|X|C|M|D|L)+"))
{
throw new ArgumentException("Invalid numeral!!");
}

        //actual validation that matters (based on http://en.wikipedia.org/wiki/Roman\_numerals): 
        //The symbols "I", "X", "C", and "M" can be repeated three times in succession, but no more. "D", "L", and "V" can never be repeated.
        string invalidSequences = "(XXXX+)|(IIII+)|(CCCC+)|(MMMM+)|(DD+)|(LL+)|(VV+)";

        if (Regex.IsMatch(romans, invalidSequences))
        {
            throw new ArgumentException("Invalid sequence!!");
        }

        int result = 0;

        result += Regex.Matches(romans, "IV").Count \* 4;
        romans = Regex.Replace(romans, "IV", string.Empty);

        result += Regex.Matches(romans, "IX").Count \* 9;
        romans = Regex.Replace(romans, "IX", string.Empty);

        result += Regex.Matches(romans, "XL").Count \* 40;
        romans = Regex.Replace(romans, "XL", string.Empty);

        result += Regex.Matches(romans, "XC").Count \* 90;
        romans = Regex.Replace(romans, "XC", string.Empty);

        result += Regex.Matches(romans, "CD").Count \* 400;
        romans = Regex.Replace(romans, "CD", string.Empty);

        result += Regex.Matches(romans, "CM").Count \* 900;
        romans = Regex.Replace(romans, "CM", string.Empty);

        result += romans.Count(x => x == 'I');
        romans = romans.Replace("I", string.Empty);

        result += romans.Count(x => x == 'V') \* 5;
        romans = romans.Replace("V", string.Empty);

        result += romans.Count(x => x == 'X') \* 10;
        romans = romans.Replace("X", string.Empty);

        result += romans.Count(x => x == 'L') \* 50;
        romans = romans.Replace("L", string.Empty);

        result += romans.Count(x => x == 'C') \* 100;
        romans = romans.Replace("C", string.Empty);

        result += romans.Count(x => x == 'D') \* 500;
        romans = romans.Replace("D", strin

[AspDotNetDev]

Good catch. Live long and prosper.

Thou mewling ill-breeding pignut!

[Karl Sanford]

Chris Maunder wrote:

Roman numerals to Arabic numbers

totally read this backward... at least now I have a solution for Arabic to Roman Numerals :doh:

Be The Noise

[Lost User]

#!/usr/bin/python

import sys

I=1
V=5
X=10
L=50
C=100
D=500
M=1000

a=0
b=0
c=0

for d in map(eval,sys.argv[1]):
if d > a:
b += d - c
c = 0
else:
b += c
c = d
a = d
print b + c

[Corporal Agarn]

Tried to leave a similar message earlier but CP locked. I was going to add this is not QA. :)

[jesarg]

private int ToInt(string rom)
{
int length = rom.Length;
int result = 0;
for(int loop1=0; loop1 < length; loop1++)
{
char current = rom[loop1];
char next = loop1 < length - 1 ? rom[loop1 + 1] : ' ';
switch(current)
{
case 'I':
result += next == 'V' || next == 'X' ? -1 : 1;
break;
case 'V':
result += 5;
break;
case 'X':
result += next == 'L' || next == 'C' ? -10 : 10;
break;
case 'L':
result += 50;
break;
case 'C':
result += next == 'D' || next == 'M' ? -100 : 100;
break;
case 'D':
result += 500;
break;
case 'M':
result += 1000;
break;
}
}
return result;
}

[Lost User]

Or, somewhat more tersely,

def r2d3(r,(s,M,C,X,I,z,V,L,D)=["%%s%d"%v for v in[1001,1000,100,10,1,0,5,50,500]]):
return eval("".join([
p%"+-"[eval( p%"%s>"%d%"")]
for d,p in zip(map(eval,'%sz'%r),map(eval,'s%s'%r))
][1:]))

[Luc Pattyn]

that would be where most Romans are, don't you think? :)

Luc Pattyn [My Articles] Nil Volentibus Arduum