main.dart

void main() {
 final map = {'a': [1, 2, 3], 'b': [4, 5, 6], 'c': [7, 8, 9]};
 var listOfItems = [1, 2, 3, 4, 5, 6, 7 ,8, 9]..shuffle();
  
 final mappedItems = {};
  
  int iterations = 0;
  
  for(final key in map.keys){
    
    final listOfItemsCopy = List<int>.from(listOfItems);
    final validItems = [];
    for(final item in listOfItems){
      
      if(map[key].contains(item)){
        validItems.add(item);
        listOfItemsCopy.remove(item);
      }
      iterations++;
    }
    mappedItems[key] = validItems;
    listOfItems = listOfItemsCopy;
    iterations++;
  }
  print(mappedItems);
  print('Total iterations: $iterations');
}