vector VS list in C++-优快云博客

本文深入探讨了Java中Vector与List的区别，重点分析了它们在内存使用、访问速度、插入删除操作以及缓存优化等方面的差异。Vector提供连续内存、预分配空间和快速随机访问，但迭代器在元素插入后失效；而List不提供连续内存，无预分配，插入删除灵活，但随机访问可能较慢。文章最后比较了两者在不同场景下的优势。

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vector is like ArrayList in Java.

vector:

Continuous memory.
Underlying array implementation.
Pre-allocate space for future element. This means extra space rather than necessary
Random access is fast, since looking up is index based.
No extra space for element. Just the element type itself.
Iterator is invalid after element insertions and erasures.
Insert element at the end is amortised constant time, while elsewhere is O(n).
Can re-allocate memory for the entire vector any time when you add an element.
Remove element at the end is constant time, while elsewhere is O(n).
Element erasure does not free memory

list:

Not continuous memory.
No pre-allocate space for future elements.
There are extra storage needed for node which holds the element, including pointers to the next and previous elements.
Insertion and deletion are cheap no matter where element is(No guarantee that list is faster. Needs to based on real application).
Access element can be expensive.
Iterator is still valid after insertion and deletion.

vector is a WIN over list in:

Random access
If you don't insert elements often, since vector has much better CPU cache locality than list, which means that accessing one element will make the next element very likely in the cache and can be retrieved without reading from slow RAM.

list is WIN over vector in:

Guaranteed constant time for inserting element at the end, since vector can lead to memory allocation and copying of original elements. However, vector can get amortised constant time.
Doing many insertions or erasures of elements in positions other than the end.

转载于:https://www.cnblogs.com/touchdown/p/5142490.html