Theoretical knowledge of arranging combination operations
1. Rules for arranging combination
Element container (ListView) is "absolutely positioned element group" (this element group is not set in the software; an independent absolute positioning element is an element group, and several positions adjacent elements are also an element group). It is understood that the relative positioning element is discussed by the general method of arranging combination operations (first discussing the general element first), discusses the position of the relative positioning element, and then discussing the location of the general element. In allocation issues, if each element includes at least N elements in the "Invaded" collection in the "receptor" collection, the software will tend to operate using the "Strip Law", that is, use imaginary "separator" Split all elements in the "Invasive" collection into several "temporary element groups" (there is no encoded in the software), and then determine the position of the separator according to the separation of the elements, to determine the "segmentation mode", eventually passed Multiplication principle determines all allocation. "Multi-line issues" is similar to "Insertion Problem", just on the "multi-line element can be exchanged", the discussion location of the element can be in all non-empty element containers. ★ Precautions: The target element of the relative positioning element can be an absolute positioning element, or a normal element, but absolutely cannot be relative positioning elements. (To prevent the generation of "self-positioning" elements, "relationship rings" issues "
2. Arrange the concept and difference
Arrange: General, from N different elements, all of the aligned numbers of the M (M ≤ N) elements are used, called a number of arrangements of the M elements from the n element. Combination: Generally, from N different elements, one of the M (M ≤ N) elements is taken, and a set of components from the N elements are called from the n element. The main difference between the arrangement combination is that the order of the district element is the same as the elements of the elements, as long as the order is different, it is regarded as a different arrangement. The same arrangement is the same as the same order, and the order of the elements is the same. Only when the elements are not all, they are different combinations, as long as the elements are the same, the order of the elements is different, and the same combination is.
3. Nounted Xinyi and Internal Coding
Element: A model for marking the characteristics of the characteristics of the characteristics, a bundle property, and element group properties. Space: A special element, can be used as a partition between an element, or as a hollow space that needs to be considered in combination, all spaces belong to an element group. Bundle: Two or more elements positions adjacent, and produce the same event, being considered as a whole, but the elements are different. Element group: The elemental properties (except for positioning information, and bundle properties) can be seen as the same element. Container - element bundle collection position - element positioning set Separate - element separation collection
