Counting a range of Objects within a Subset of NSSet

Question

I have created several NSSet's with specific coordinates likes so:

CoordRange     = [[NSSet alloc] initWithObjects:[NSNumber numberWithInt:-1],
                 [NSNumber numberWithInt:-3],[NSNumber numberWithInt:-7],
                 [NSNumber numberWithInt:-5],nil];

I will receive several coordinates within an NSArray. I create an NSSet from the array (GRID) to use the "isSubsetOfSet" function of NSSet. It is possible that the new NSSet (GRID) can contain a value outside CoordRange. Is there a way for me to determine if GRID contains at least four values from CoordRange.

So if GRID = [-1,-5,-7,-3,10], is there a way for me to determine if at least four of the values are a subset of CoordRange? The isSubSetOfSet will only compare the entire set/range.

Answer 1

This might not be the most efficient solution but you can iterate through the Set and check if each object is in the second set until you have 4 objects.

NSSet *coordRange     = [[NSSet alloc] initWithObjects:[NSNumber numberWithInt:-1],
                  [NSNumber numberWithInt:-3],[NSNumber numberWithInt:-7],
                  [NSNumber numberWithInt:-5],nil];
NSSet *grid = [NSSet setWithArray:@[@-1,@-2,@-7,@-3,@10]];

__block NSInteger count = 0;

[grid enumerateObjectsUsingBlock:^(id  _Nonnull obj, BOOL * _Nonnull stop) {
    if ([coordRange containsObject:obj]) count++;
    if (count >= 4) *stop = YES;
}];

NSLog(@"count: %lu", count);