Fastest way to check if an array contains the same objects of another array

Question

The goal is to compare two arrays as and check if they contain the same objects (as fast as possible - there are lots of objects in the arrays). The arrays cannot be checked

Answer 1

Use containsObject: method instead of iterating the whole array.

NSArray *array;
array = [NSArray arrayWithObjects: @"Nicola", @"Margherita",                                       @"Luciano", @"Silvia", nil];
if ([array containsObject: @"Nicola"]) // YES
  {
    // Do something
  }

like this

+ (BOOL)arraysContainSameObjects:(NSArray *)array1 andOtherArray:(NSArray *)array2 {
    // quit if array count is different
    if ([array1 count] != [array2 count]) return NO;

    BOOL bothArraysContainTheSameObjects = YES;

    for (id objectInArray1 in array1) {

        if (![array2 containsObject:objectInArray1])
        {
            bothArraysContainTheSameObjects = NO;
            break;
        }

    }

    return bothArraysContainTheSameObjects;
}