/// <summary>
/// Constructor for the Problem class, initializes all data regarding one Particular problem
/// </summary>
/// <param name="problemID">ID of the Problem</param>
protected Problem(Global.Problems problemID)
{
ProblemID = problemID;
metaData = new ProblemMetaData(problemID);
Name = metaData.GetName();
Description = metaData.GetDescription();
Implementations = metaData.GetImplementations();
Instruction = metaData.GetInstruction();
DefaultSubMethod = metaData.GetDefaultSubMethod();
}
/// <summary>
/// Get the particular Problem object based on the option chosen by user
/// </summary>
/// <param name="problem">Problem ID</param>
/// <returns>Respective problem object</returns>
static Problem ProblemFactory(Global.Problems problem)
{
switch (problem)
{
case Global.Problems.RodCutting: return(new RodCutting());
case Global.Problems.LongestCommonSubSequence: return(new LongestCommonSubsequence());
default: return(null);
}
}
/// <summary>
/// Constructor to initialize properties
/// </summary>
/// <param name="problemID">ID of the particular problem, must be of type Problems enum</param>
public ProblemMetaData(Global.Problems problemID)
{
doc = XDocument.Load(xmlFilePath);
ProblemID = problemID;
/*It is proved that .Where(predicate).First() is faster than .First(predicate), though it may sound very much counter-intuitive but it is true,
* If any one can prove me otherwise or explain this weird behaviour, I am all ears
* My guess is .First uses simple foreach loop whereas .Where uses many different iterators for different purposes, it may give some edge (by optimizing) to .Where
* - Diptarag
*/
try
{
problemElement = doc.Descendants("Problem").Where(node => Convert.ToInt32(node.Attribute("Id").Value) == (int)ProblemID).First();
}
catch
{
throw new DynamicProgrammingException("It seems Id attribute of Problem element has been changed in ProblemDescription.xml or some element is deleted. Please do not change the content of the xml");
}
}
