vector的一些操作

做题的时候，碰到vector的一些函数，特此记下来。

1.reserve(n): Requests that the vector capacity be at least enough to contain n elements

2.lower_bound

1)lower_bound (ForwardIterator first, ForwardIterator last,                               const T& val);

2)lower_bound (ForwardIterator first, ForwardIterator last,                               const T& val, Compare comp);

Returns an iterator pointing to the first element in the range [first,last) which does not compare less than val.

3.upper_bound

1)upper_bound (ForwardIterator first, ForwardIterator last,                               const T& val);

2)upper_bound (ForwardIterator first, ForwardIterator last,

                               const T& val, Compare comp);

Returns an iterator pointing to the first element in the range [first,last) which compares greater than val.

4.insert
void insert (iterator position, InputIterator first, InputIterator last);
从position开始，插入[first, last)的元素