Array / ArrayList / Linked List时间复杂度对比图

Array / ArrayList / Linked List时间复杂度对比图

This is a little brief about the time complexity of the basic operations supported by Array, Array List and Linked List data structures. And as a result, we can judge when each one of these data structure will be of best use

Operation Array ArrayList Singly Linked List
Read (any where) O(1) O(1) O(n)
Add/Remove at end O(1) O(1) O(n)
Add/Remove in the interior O(n) O(n) O(n)
Resize O(n) N/A N/A
Find By position O(1) O(1) O(n)
Find By target (value) O(n) O(n) O(n)

When is it the best to use each one of the mentioned above data structures?

Array:
——————-
1- Excessive read, as time complexity of read is always O(1)
2- Random access to element using index: if you

 ArrayList:
——————-1- Excessive read
2- Random access to elements using their index
3- More flexible in coding
4- Effective use of memory space as items get allocated as needed

LinkedList:
——————- 
1- Effective use of memory space as items get allocated as needed
2- Excessive Add/Remove of elements (It’s better than ArrayList, because since array list items get stored in memory in adjacent place. when adding a new element in the middle of the array list, all  the items after the inserted one have to be shifted, with Linked list the new item gets injected in the list without the need to shift the other items as they are not adjacent in the memory)

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