Check IF one String contains the same characters as another string

Question

I am trying to write a function which will allow me to determine whether one NSString* contains the characters of another NSString*. As an example, refer to the below scenario:

NSString *s1 = @"going";
NSString *s2 = @"ievngcogdl";

So essentially when the comparison between these 2 strings occurs, it should return true as the first string s1 has the same characters of the second string s2. Could I use an NSCountedSet? I know that this class has a method containsObject:(id) although I don't think that will solve my problem. Is there any other ways in completing this function and provide me the required results?

Answer 1

I think this method could be rather slow, but I would still favour it over [NSString rangeOfCharacterFromSet:], which requires creating an NSCharacterSet object per comparison:

- (BOOL)string:(NSString *)string containsAllCharactersInString:(NSString *)charString {
    NSUInteger stringLen = [string length];
    NSUInteger charStringLen = [charString length];
    for (NSUInteger i = 0; i < charStringLen; i++) {
        unichar c = [charString characterAtIndex:i];
        BOOL found = NO;
        for (NSUInteger j = 0; j < stringLen && !found; j++)
            found = [string characterAtIndex:j] == c;
        if (!found)
            return NO;
    }
    return YES;
}