UITableView可以分普通模式和Editing模式两种,这里我们着重讨论Editing模式,Editing模式中又分三种操作:Insert.Delete. Reallocted.Insert和Delete针对数据源内容的修改,而Reallocated是针对数据源位置的修改.下面分别讨论. 一.Insert Or Delete 当UITableView接收到 setEditing:animated:时,它会将同样的消息转发给每一个可见行,大致会经历如下步骤,引用至官方: The table…
Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an item val from the collection if present. getRandom:…
Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element fro…