The place to start searching for the correct point of insertion. (Insertion can occur in amortized constant time, instead of logarithmic time, if the insertion point immediately follows _Where.

• 为什么要这样,难道不是每次插入的时候都从尾部插入吗?回复--------------为什么要这样,难道不是每次插入的时候都从尾部插入吗?