Self doubt finding complexity algorithms where study this topic

Question

1.What is the time complexity for insertion in binary tree in worst case?

• A. O(1)
• B. O(log n)
• C. O(n)
• D. O(n log n)

2.

An array ′A′has n distinct integers. What is the tightest time complexity to check A[i]=i for some i. Consider all elements of array within range from 1 to n.

1. O(n2)
2. O(1)
3. O(n)
4. O(logn)

PS:For solving these types of questions please suggest  study resource I already know these are my weak topic15  day before exam but could't improve till now

Comments

AFAIK, Geeksforgeeks is better site for algo and ds

---

Thanks
Should we do lots of problem  and again study theory portion to understand how algorithms work of particular subtopic rather than memorising by heart  result (complexity). Again thanks got the way of study algorithms