Quick Sort in Objective-C

Quick Sort in

Objective-C

Welcome to the Quick Sort in Objective-C page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

#import <Foundation/Foundation.h>

@interface NSString (Parsing)
- (nullable NSArray<NSNumber*>*)strictIntegerList;
@end

@implementation NSString (Parsing)

- (NSArray<NSNumber*>*)strictIntegerList {
    NSArray<NSString*>* parts = [self componentsSeparatedByString:@","];
    NSMutableArray<NSNumber*>* results =
        [NSMutableArray arrayWithCapacity:parts.count];
    NSCharacterSet* invertedDigits =
        NSCharacterSet.decimalDigitCharacterSet.invertedSet;

    for (NSString* raw in parts) {
        NSString* s = [raw stringByTrimmingCharactersInSet:
                               NSCharacterSet.whitespaceAndNewlineCharacterSet];
        if (s.length == 0) return nil;

        NSString* core = ([s hasPrefix:@"-"] || [s hasPrefix:@"+"])
                             ? [s substringFromIndex:1]
                             : s;
        if (core.length == 0 ||
            [core rangeOfCharacterFromSet:invertedDigits].location !=
                NSNotFound)
            return nil;

        [results addObject:@(s.longLongValue)];
    }
    return (results.count >= 2) ? results : nil;
}

@end

static void quickSortRange(NSMutableArray<NSNumber*>* array, NSInteger left,
                           NSInteger right) {
    if (left >= right) return;

    NSInteger i = left;
    NSInteger j = right;
    long long pivot = array[left + (right - left) / 2].longLongValue;

    while (i <= j) {
        while (array[i].longLongValue < pivot) i++;
        while (array[j].longLongValue > pivot) j--;

        if (i <= j) {
            [array exchangeObjectAtIndex:i withObjectAtIndex:j];
            i++;
            j--;
        }
    }

    quickSortRange(array, left, j);
    quickSortRange(array, i, right);
}

@interface NSArray (Sorting)
- (NSArray<NSNumber*>*)sortedArrayUsingQuickSort;
@end

@implementation NSArray (Sorting)

- (NSArray<NSNumber*>*)sortedArrayUsingQuickSort {
    if (self.count < 2) return self;

    NSMutableArray<NSNumber*>* buffer = [self mutableCopy];
    quickSortRange(buffer, 0, buffer.count - 1);

    return buffer;
}

@end

int main(int argc, const char* argv[]) {
    @autoreleasepool {
        const char* usage =
            "Usage: please provide a list of at least two integers to sort "
            "in the format \"1, 2, 3, 4, 5\"";

        if (argc < 2) {
            puts(usage);
            return 1;
        }

        NSArray<NSNumber*>* numbers = [@(argv[1]) strictIntegerList];

        if (!numbers) {
            puts(usage);
            return 1;
        }

        NSString* output = [[numbers sortedArrayUsingQuickSort]
            componentsJoinedByString:@", "];

        puts(output.UTF8String);
    }

    return 0;
}

Quick Sort in Objective-C was written by:

• niftycode
• rzuckerm
• Ștefan-Iulian Alecu

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.