Question

I have input as two arrays shown below

NSArray *array1=[[NSArray alloc]initWithObjects:@"1",@"2",@"3", nil];

NSArray *array2=[[NSArray alloc]initWithObjects:@"1",@"2",@"1", nil];

the output should resemble like this.
the same element should be cancelled only one time.

NSArray *array3=[[NSArray alloc]initWithObjects:@"1",@"2", nil];

THANKS IN ADVANCE…..

Answer 1

Use NSCountedSet for the above situation

 NSMutableArray *array1=[[NSMutableArray alloc]initWithObjects:@"r",@"a",@"r",@"r",@"r", nil]; 

    NSArray *array2=[[NSArray alloc]initWithObjects:@"b",@"c",@"r", nil];


    NSMutableSet *setOne = [NSMutableSet setWithArray: array1];
    NSSet *setTwo = [NSSet setWithArray: array2];

    [setOne unionSet:setTwo];

    NSArray *arrayOneResult = [setOne allObjects];

    NSLog(@"%@",arrayOneResult);

    NSMutableArray *resultArray = [[NSMutableArray alloc]init];

    NSCountedSet *set = [[NSCountedSet alloc] initWithArray:arrayOneResult];

    for (id item in set)
    {

        NSCountedSet *set1 = [[NSCountedSet alloc] initWithArray:array1];
        NSCountedSet *set2 = [[NSCountedSet alloc]initWithArray:array2];

        int diff = abs([set1 countForObject:item] - [set2 countForObject:item]);

        for (int  i = 0 ;i < diff ;i++ ) {
            [resultArray addObject:item];
        }


    }

    NSLog(@"the array : %@",resultArray   );