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stevenhuey's solution

to Scrabble Score in the Objective-C Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

Given a word, compute the scrabble score for that word.

Letter Values

You'll need these:

Letter                           Value
A, E, I, O, U, L, N, R, S, T       1
D, G                               2
B, C, M, P                         3
F, H, V, W, Y                      4
K                                  5
J, X                               8
Q, Z                               10

Examples

"cabbage" should be scored as worth 14 points:

  • 3 points for C
  • 1 point for A, twice
  • 3 points for B, twice
  • 2 points for G
  • 1 point for E

And to total:

  • 3 + 2*1 + 2*3 + 2 + 1
  • = 3 + 2 + 6 + 3
  • = 5 + 9
  • = 14

Extensions

  • You can play a double or a triple letter.
  • You can play a double or a triple word.

Setup

There are two different methods of getting set up to run the tests with Objective-C:

  • Create an Xcode project with a test target which will run the tests.
  • Use the ruby gem objc as a test runner utility.

Both are described in more detail here: http://exercism.io/languages/objective-c

Submitting Exercises

When submitting an exercise, make sure your solution file is in the same directory as the test code.

The submit command will look something like:

exercism submit <path-to-exercism-workspace>/objective-c/scrabble-score/ScrabbleScore.m

You can find the Exercism workspace by running exercism debug and looking for the line beginning with Workspace.

Source

Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

ScrabbleScoreTest.m

#import <XCTest/XCTest.h>

#if __has_include("ScrabbleScoreExample.h")
# import "ScrabbleScoreExample.h"
# else
# import "ScrabbleScore.h"
#endif

@interface ScrabbleScoreTest : XCTestCase

@end

@implementation ScrabbleScoreTest

- (void)testEmptyWordScoresZero {
    XCTAssertEqual(0, [[[ScrabbleScore alloc] initWithWord:@""] score]);
}

- (void)testWhitespaceScoresZero {
    XCTAssertEqual(0, [[[ScrabbleScore alloc] initWithWord:@" \t\n"] score]);
}

- (void)testNilScoresZero {
    XCTAssertEqual(0, [[[ScrabbleScore alloc] initWithWord:nil] score]);
}

- (void)testScoresVeryShortWord {
    XCTAssertEqual(1, [[[ScrabbleScore alloc] initWithWord:@"a"] score]);
}

- (void)testScoresOtherVeryShortWord {
    XCTAssertEqual(4, [[[ScrabbleScore alloc] initWithWord:@"f"] score]);
}

- (void)testSimpleWordScoresTheNumberOfLetters {
    XCTAssertEqual(6, [[[ScrabbleScore alloc] initWithWord:@"street"] score]);
}

- (void)testComplicatedWordScoresMore {
    XCTAssertEqual(22, [[[ScrabbleScore alloc] initWithWord:@"quirky"] score]);
}

- (void)testScoresAreCaseInsensitive {
    XCTAssertEqual(41, [[[ScrabbleScore alloc] initWithWord:@"OXYPHENBUTAZONE"] score]);
}

- (void)testConvenientScoring {
    XCTAssertEqual(13, [ScrabbleScore score:@"alacrity"]);
}

@end
//
//  ScrabbleScore.m
//  ScrabbleScore
//
//  Created by Steve Huey on 6/13/17.
//  Copyright © 2017 Steve Huey. All rights reserved.
//

#import "ScrabbleScore.h"

@interface ScrabbleScore ()
@property (nonatomic, copy) NSString* word;

- (NSUInteger)scoreForLetter:(unichar)c;
- (NSDictionary*)letterValues;
@end

@implementation ScrabbleScore
+ (NSUInteger)score:(NSString*)word
{
   ScrabbleScore* scrabble = [[ScrabbleScore alloc] initWithWord:word];
   
   if (scrabble)
   {
      return [scrabble score];
   }
   else
   {
      return 0;
   }
}

- (instancetype)initWithWord:(NSString*)word
{
   self = [super init];
   
   if (self)
   {
      _word = [word copy];
   }
   
   return self;
}

- (NSUInteger)score
{
   NSUInteger score = 0;
   
   for (NSUInteger i = 0; i < [self.word length]; ++i)
   {
      score += [self scoreForLetter:[self.word characterAtIndex:i]];
   }
   
   return score;
}

- (NSUInteger)scoreForLetter:(unichar)c
{
   NSString* letter = [[NSString stringWithFormat:@"%c", c] uppercaseString];
   
   NSUInteger score = 0;
   NSDictionary* letterValues = [self letterValues];
   
   for (NSNumber* value in letterValues)
   {
      NSString* letters = letterValues[value];
      
      if ([letters containsString:letter])
      {
         score = [value unsignedIntegerValue];
         break;
      }
   }
   
   return score;
}

- (NSDictionary*)letterValues
{
   static NSDictionary* letterValues;
   
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
      letterValues = @{@(1): @"AEIOULNRST",
                       @(2): @"DG",
                       @(3): @"BCMP",
                       @(4): @"FHVWY",
                       @(5): @"K",
                       @(8): @"JX",
                       @(10): @"QZ"};
   });
   
   return letterValues;
}

@end

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