map映照容器的元素数据由一个键值和一个映照数据组成的，他也是采用红黑树实现，插入元素的键值不允许重复，默认从小到大排-Map of the container element data from the shine upon a key value and a mapping data of composition, he is also using red and black tree realization, the elements of the key value not allowe