I am looking if there is an "easy" or simple way to make an array of something, Lets say Icecreams.. this would be a class of icecream with various Attributes (ID, flavour, Size, scoops), i would like to run an array that gathers every ice cream ordered and then searches through this list for any duplicate values (2+ same size)
First idea i had was a for loop that creates the array than grabs the ice cream ID for the first instance, and checks its "flavour" against the array, if no duplicate is found the ID is increased by 1 (ID++) and then that Ice creams flavour is ran in the array, if a match is found i would set a Boolean to true.
Every approach i seem to take appears to be rather long winded and i haven't got one working as of yet. hoping some fresh/more experienced eyes would help on this.
In answer to below;
The XML would hold something like below
<iceCream id=1>
<flavour>chocolate</flavour>
<scoops>5</scoops>
</iceCream>
<iceCream id=2>
<flavour>banana</flavour>
<scoops>2</scoops>
</iceCream>
I would want to use drools (probably an array list?) to gather each icecream tag and allow me to check if any of the icecreams have the same flavour and output something (set a boolean to true) if a match is found, My understand was to make an array then run each icecream though the array by using its ID to identify it and inside each loop do ID +1 (int ID = 1) then in the lopp ID++. Aswell as search through the flavour childtag.
int ID = 0;
boolean match = false;
ArrayList iceCreams = new ArrayList($cont.getIceCreams());
for(iceCream $Flavour: (ArrayList<iceCream>)iceCreams)
{
ID++
if($Flavour.getFlavour().equals(icecream with id of (ID variable).getFlavour)
{
match = true;
}
}
if(match)
{etc etc etc}
Something along these lines if this helps?
1) If you have control over the first array creation, why dont you make sure that while insertion, you insert only the icecreams that are unique. So, while you are inserting into the array say ID=1, first iterate through the array and check if there is an icecream in the array with ID as 1, if not you put this into the array and do other stuff.
2) Searching part: now while inserting, make sure that you are doing so based on the ascending oder of IDs, so you can perform binary search for the same.
Note: I dont know drools, i have just posted a logic as per my understanding of the problem.
I don't know drools either, but I'll post the some pseudo code for what I think you are trying to accomplish:
for(i = 0; i < len(ice_cream_array); i++)
{
for(j = (i + 1); j < len(ice_cream_array); j++)
{
if (ice_cream_array[i] == ice_cream_array[j])
break from inner loop
else
there is no match
}
}
You may also want to look up bubble sorts and binary searches.
Related
I'm working on a Scrabble assignment and I'm trying to assign values to letters. Like in Scrabble, A, E, I, O, U, L, N, S, T, R are all equal to 1. I had some help in figuring out how to add the score up once I assign values, but now I'm trying to figure out how to assign values. Is there a way to create one variable for all the values? That doesn't really make sense to me.
I was also thinking I could do an if-else statement. Like if the letter equals any of those letters, value = 1, else if the letter equals D or G, value = 2 and so on. There are 7 different scores so it's kind of annoying and not efficient, but I'm not really sure what a better way might be. I'm new to programming, a novice, so I'm looking for advice that takes my level into account.
I have started my program by reading words from a text file into an arraylist. I successfully printed the arraylist, so I know that part worked. Next I'm working on how to read each character of each word and assign a value. Last, I will figure out how to sort it.
it's me from the other question again. You can definitely do an if-statement, but if I'm not wrong Scrabble has 8 different values for letters, so you would need 8 “if”s and also since there are around 25 letters (depending on language) you would have to handle all 25 some way in the if-statements which would be quite clunky in my opinion.
I think the best option is to use a Hash-table. A hash-table is basically like a dictionary where you look up a key and get a value. So I would add each letter as a key and keep the corresponding value as the value. It would look like this:
//initialize empty hash map
Hashtable<String, Integer> letterScores = new Hashtable<>();
//now we can add values with "put"
letterScores.put("A",1)
letterScores.put("B",3)
letterScores.put("X",8)
//etc
To access an element from the hash table we can use the "get"-method.
//returns 1
letterScores.get("A")
So when looping through our word we would essentially get something like this to calculate the value of the word:
int sumValue = 0;
for(int i =0; i < word.length(); i++)}
sumValue += letterScores.get(word.charAt(i))
}
For each character we grab the value entry from the letterScores hash table where we have saved all our letter's corresponding values.
I'm looking for the fastest algorithm that can find a set of words matching another set of words in a list of 9 million records.
Problem: I have a list with almost 100,000 sets of words and I need to search for a match of each of the word set in another list of 9 million sets of words.
My current solution goes like this, I read all the records (from a text file) and keep in memory (in form of an array, let's call it 'search list'). While building this array, I sort the set of words alphabetically and once all the word sets are added, I sort the whole list. I do the same with the other big list, let's call that 'data list'.
Now I iterate over each of elements in my search list and try to find a match. Once a match is found I remember the position at which it matched and the next search I do from the same position. This saves me from iterating the whole data list again and again for each element in the search list.
I assumed it to be super fast but unfortunately, it's not. It almost takes 15 to 20 mins to complete full iteration of the search list. This is not acceptable.
Here is a snippet of my code
int lastPointer = 0
for(int i=0; i<search list.size(); i++){
def this_matched_out = []
inmem_json_arr[i][0]
for(int j=lastPointer; j<data list.size(); j++){
if(data list[j].containsAll(search list[i])){
this_matched_out.add(data list[j])
lastPointer = j
}
}
if(this_matched_out.size()>0) - println "found a match for search "+list[i]
else println "No match found for "+list[i]
}
Can anybody suggest me a better algorithm or am I doing anything wrong here?
Use a hash table. A lookup takes O(1) time no matter how big your set of words is.
so the title essentially says it all. I am writing a symbol table in c++ for a compiler project I am working on, and all is going well except for looking up identifiers in the table.
So this is how I store into the table (pseudo like):
vector<symbolTable*>* symbolStack = new symbolTable();
//where a symbolStack is a vector of unordered_maps (symbolTables),
//each iteration in vector referencing a new block of code.
string* check = new string(root->children[0]->lexicode->c_str());
symbol* sym = new symbol();
...... //setting sym info
symbol_entry pair = make_pair(check, test)
//the unordered_map has keys of (string*, symbol*)
symbolStack[tableNumber]->insert(pair);
I am pretty solid that this works, as I have tested printing the size/infos from the map and it all seems to be storing as expect. Here is where the problem is happening for me (this takes place in a different function later):
for(int i = 0; i =< tableNumber;i++){
auto finder = symbolStack[i]->find(checkS) //checkS == check from above
if(finder == symbolStack[i]->end()) cout<<not found;
else cout<<we did it!!!!
My else is never reached. However, if I do this assuming the string*->c_str() == "test":
cout<<string->c_str(); // prints out "test"
cout<<finder->second->c_str() //prints out "test".
So the question. Why is it finding the key, and knowing it found the key, but at the same time returning that is has reached the end of the symbol stack without finding it? I have been trying to figure this out for a good 4 days solid now. Is it that my pointers are somehow off? Any insight is appreciated greatly.
So somewhat answer to my own question.
First I will say this: I have concluded the comparison with find() or similar methods do not work because for some reason the pointers are not matching up. I have no clue why this is still, or what I am doing wrong.
What I did to solve my issue and complete my code is this:
for(int k = 0; k<= tableNumber; k++){
unordered_map<string*,symbol*>::iterator it;
for(it = symbolStack[k]->begin(); it != symbolStack[k]->end(); it++)
{
string a = targetString->c_str();
string b = it->first->c_str();
if(a.compare(b) == 0) cout<<"You have found the match! \n";
}
}
}
So this answers how to get it working pragmatically if somebody else is in a similar ship, however not really answers why my other attempt failed other than noticing the pointer values were different.
In symbolTable you store pointers to strings as keys, not strings themselves. Therefore unordered_map compares pointers, not strings, and cannot find matching items. When you reconstruct the key string (as in your answer, using string b = it->first->c_str()), the comparison on strings works again. So, either you need to store string instead of string * in symbolTable, or you need to provide your own comparison function that will compare keys of type string *.
I have a variable titled F.
Describe F returns:
F: {group: bytearray,indexkey: {(indexkey: chararray)}}
Dump F returns:
(321,{(CHOW),(DREW)})
(5011,{(CHOW),(DREW)})
(5825,{(TANNER),(SPITZENBERGER)})
(16631,{(CHOW),(DREW)})
(34299,{(CHOW),(DREW)})
(35044,{(TANNER),(SPITZENBERGER)})
(65623,{(CHOW),(DREW)})
(74597,{(SPITZENBERGER),(TANNER)})
(83499,{(SPITZENBERGER),(TANNER)})
(90257,{(SPITZENBERGER),(TANNER)})
What I need is to produce an output that looks like this (only 1st row as an example):
(321,DREW,{(CHOW)})
I've tried using deference to pull out the first element by using this:
G = FOREACH F generate indexkey.$0;
But, this still returns the whole tuple.
Can anyone suggest a method for doing this? I was under the impression that the deference operator should allow me to do this.
Thanks in advance!
Daniel
You can't index into bags like that. The reason for that is bags don't have any notion of ordering. Selecting the first item in a bag should be treated as picking a random one.
Either way, if you want only one item instead of all of them you can used a nested FOREACH to pull a LIMIT of 1:
first = FOREACH F {
lim = LIMIT indexkey 1;
GENERATE group, lim;
}
(disclaimer: I can't test this code right now, if it doesn't work let me know. Hopefully you can get the gist)
You can take this a bit further and FLATTEN it to remove the bag of one item entirely, but be careful in that if the bag is empty i think you throw away the entire record in this case.
first = FOREACH F {
lim = LIMIT indexkey 1;
GENERATE group, FLATTEN(lim);
}
Let's assume that we have the list of loans user has like below:
loan1
loan2
loan3
...
loan10
And we have the function which can accept from 2 to 10 loans:
function(loans).
For ex., the following is possible:
function(loan1, loan2)
function(loan1, loan3)
function(loan1, loan4)
function(loan1, loan2, loan3)
function(loan1, loan2, loan4)
function(loan1, loan2, loan3, loan4, loan5, loan6, loan7, loan8, loan9, loan10)
How to write the code to pass all possible combinations to that function?
On RosettaCode you have implemented generating combinations in many languages, choose yourself.
Here's how we could do it in ruby :
loans= ['loan1','loan2', ... , 'loan10']
def my_function(loans)
array_of_loan_combinations = (0..arr.length).to_a.combination(2).map{|i,j| arr[i...j]}
array_of_loan_combinations.each do |combination|
//do something
end
end
To call :
my_function(loans);
I have written a class to handle common functions for working with the binomial coefficient, which is the type of problem that your problem falls under. It performs the following tasks:
Outputs all the K-indexes in a nice format for any N choose K to a file. The K-indexes can be substituted with more descriptive strings or letters. This method makes solving this type of problem quite trivial.
Converts the K-indexes to the proper index of an entry in the sorted binomial coefficient table. This technique is much faster than older published techniques that rely on iteration. It does this by using a mathematical property inherent in Pascal's Triangle. My paper talks about this. I believe I am the first to discover and publish this technique, but I could be wrong.
Converts the index in a sorted binomial coefficient table to the corresponding K-indexes. I believe it might be faster than the link you have found.
Uses Mark Dominus method to calculate the binomial coefficient, which is much less likely to overflow and works with larger numbers.
The class is written in .NET C# and provides a way to manage the objects related to the problem (if any) by using a generic list. The constructor of this class takes a bool value called InitTable that when true will create a generic list to hold the objects to be managed. If this value is false, then it will not create the table. The table does not need to be created in order to perform the 4 above methods. Accessor methods are provided to access the table.
There is an associated test class which shows how to use the class and its methods. It has been extensively tested with 2 cases and there are no known bugs.
To read about this class and download the code, see Tablizing The Binomial Coeffieicent.
It should not be hard to convert this class to the language of your choice.
To solve your problem, you might want to write a new loans function that takes as input an array of loan objects and works on those objects with the BinCoeff class. In C#, to obtain the array of loans for each unique combination, something like the following example code could be used:
void LoanCombinations(Loan[] Loans)
{
// The Loans array contains all of the loan objects that need
// to be handled.
int LoansCount = Loans.Length;
// Loop though all possible combinations of loan objects.
// Start with 2 loan objects, then 3, 4, and so forth.
for (int N = 2; N <= N; N++)
{
// Loop thru all the possible groups of combinations.
for (int K = N - 1; K < N; K++)
{
// Create the bin coeff object required to get all
// the combos for this N choose K combination.
BinCoeff<int> BC = new BinCoeff<int>(N, K, false);
int NumCombos = BinCoeff<int>.GetBinCoeff(N, K);
int[] KIndexes = new int[K];
// Loop thru all the combinations for this N choose K.
for (int Combo = 0; Combo < NumCombos; Combo++)
{
// Get the k-indexes for this combination, which in this case
// are the indexes to each loan in Loans.
BC.GetKIndexes(Loop, KIndexes);
// Create a new array of Loan objects that correspond to
// this combination group.
Loan[] ComboLoans = new Loan[K];
for (int Loop = 0; Loop < K; Loop++)
ComboLoans[Loop] = Loans[KIndexes[Loop]];
// Call the ProcessLoans function with the loans to be processed.
ProcessLoans(ComboLoans);
}
}
}
}
I have not tested the above code, but in general it should solve your problem.