p>获得插入点的效率至少是没有问题的 - 每次插入时，不断地改变现有数据的效率就会很低。

The efficiency of obtaining the insertion point won't matter in the least - it will be dwarfed by the inefficiency of constantly shuffling the existing data up every time you do an insertion.

为此使用std :: deque，这是它的设计目的。

Use std::deque for this, that's what it was designed for.