I'm quite a fan of unit testing (not necessarily TDD), and while refactoring methods of EKSearchStuff, EKSortStuff and EKArrayStuff I found myself in the position of having to check the console (for the output of the main file) to see if I broke something or not. I would like to create a unit tests suite (if you don't mind I would use Kiwi framework) to make it easier in the future to refactor things and also for new people to add new algorithms. Of course I won't be able to write the whole suite by myself, so I will need some help. What do you think?

The changed proposed #14 is good but only partially - it is good to know that Apple's reverseObjectEnumerator does its job - and as of Apple recommends to "use highest API possible" - it would be a better choice than to implement it by hands, but I think it would still be great to have both variant of methods to be kept in EKAlgorithms.

What I suggest is to keep both methods side by side, the only trick is again to invent a good convention to handle this:

My initial thought was something like:

+ (NSArray *)reversedArrayWithArray:(NSArray *)arrayToReverse
+ (NSArray *)native_reversedArrayWithArray:(NSArray *)arrayToReverse

or

+ (NSArray *)reversedArrayWithArray:(NSArray *)arrayToReverse
+ (NSArray *)CocoaImplementation_reversedArrayWithArray:(NSArray *)arrayToReverse

But I personally dislike using underscores in method names that is why I also thought about something like

+ (NSArray *)reversedArrayWithArray:(NSArray *)arrayToReverse
+ (NSArray *)reversedArrayWithArrayImplementedByCocoa:(NSArray *)arrayToReverse

For now I think that "CocoaImplementation_reversedArrayWithArray" is the best naming convention to be used for methods showing usage of highest-level of API suggested by Cocoa.

Let me know what you think.

Here are more examples we could write using Cocoa API:

Index of maximum element: [array valueForKeyPath:@"@max.integerValue"] Binary search from awesome objc.io Issue n7, Binary Search.

Hello, @EvgenyKarkan.

How about adding section with similar repositories? I think this growing one is a good candiate to start section.

I haven't been doing anything on this algorithms topic during these latest months because of almost entire focus on patterns/architecture area so no contributions :smile: Anyway I like it a lot that we created and now have this basic base of algorithms just in case if a need in some of them raises! Good work!

Thanks,

Stanislaw

Please fix:

EKAlgorithmsExamples crashes (XCode 5.1.1, OS 10.9): main.m, line 72, message: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[NSDictionary dictionaryWithObjectsAndKeys:]: second object of each pair must be non-nil. Or, did you forget to nil-terminate your parameter list?'

[oneArray addObject:[NSDictionary dictionaryWithObjectsAndKeys:@"EKAlgorithms100", nil]];

should be:

[oneArray addObject:[NSDictionary dictionaryWithObjectsAndKeys:@"EKAlgorithms100", someKey, nil]];

After taking a look at the classes, I found that most of the methods could be simplified if moved to categories instead of their own class.

Example: + (NSUInteger)indexOfMaximumElementInArray:(NSArray *)array; could become - (NSUInteger)indexOfMaximumElement;

+ (NSInteger)indexOfObjectViaLinearSearch:(id)object inArray:(NSArray *)arrayToSearch; could become - (NSInteger)indexOfObjectViaLinearSearch:(id)object;

+ (NSMutableArray *)bubbleSortedArrayWithUnsortedArray:(NSMutableArray *)unsortedArray; could become - (NSArray *)bubbleSort;

+ (BOOL)isGivenStringPalindrome:(NSString *)string; could become - (BOOL)isPalindrome;

and so on.. Do you agree with this? If yes, I will move methods to categories so that their interface will be easier to use.

Following my previous issue #34:

I think that your original implementation of reversedArrayWithArray can be improved by using the technique similar to what is used in #30 and #31:

Only first n/2 elements should be traversed exchanging i and count-i on each step - the middle element (if it exists - stays one the same position - hm, nice!).

Let me know, what do you think.

hi i once wrote longest common subsequence and Levenshtein distanc algorithm as an NSString category in this tiny reop but when i came across this repo of yours i feel that maybe i could add the two methods into your project. is it okay for me to make a pull request then?

Ported to iOS. Seems to work. #87

iOS doesn't implement NSComparisonMethods protocol since the one was made for MacOSX's scripting support. iOS doesn't deal with scripts.

Those methods, leaving scripting behind, are identical to the usual compare: and isEqual:.

Also had to change a class of weight property of EKEdge from NSObject to NSNumber. Why NSObject in the first place?

Made preprocessor's statements around imports in addition to ones in .h and .m files of iOS-only categories to protect them from IDE's import optimisations and suppression of warnings.

Hi, I'm new to programming, and I chose Objective-C as my first programming language. I've been search for a while but I couldn't find any book about Data Structure and Algorithms in Objective-C. So can you give me some source for learning these things.

Thanks.

All works fine now.

There were problems with MapKit on OS X - it is supported only in 10.9, while Travis machines still have 10.8.5. I mocked all the geometry needed for now, so EKAlgorithms does not depend on any external frameworks: nor CoreLocation, nor MapKit.

Before today I wasn't aware that besides creating mutable array -[NSArray mutableCopy] also makes copy of each element.

Now, having this in mind, I am pretty sure, that for general consistency of the whole algorithms base we need to eliminate all these mutableCopy strings and replace them with corresponding [NSMutableArray arrayWithArray:] strings.

Every single loop will be faster without any additional computations and methods call. E.g "[array count]" in loop such as "for (NSUinteger i = 0; i < [array count]; i++)" should be extracted to independent local variable NSUinteger counter = [array count]. So the loop will be faster & look like "for (NSUinteger i = 0; i < counter; i++)".