What is the time complexity of the contains operation and the find operation for both implementations?

Contains O (n) and find O (n).

Explanation:

Both methods are used in Java. The time complexity of both contains and find methods is O (n). This is because both of them work like a linear search works both the methods they traverse the list or the array elements one by one to look for the element. So iterating over each element gives the time complexity of O (n).