Epic Skills Assessment Algorithmic Problem Solving 3

Question 1

Which algorithm strategy makes the locally optimal choice at each step without reconsidering past decisions?

Accepted Answer

Greedy

Answer

Greedy algorithms commit to the best immediate option at each step, which works when local optima lead to a global optimum.

Question 2

What is a 'sentinel value' used for in algorithms?

Accepted Answer

A placeholder that simplifies boundary condition checks

Answer

A sentinel is a special value (e.g., −∞ or null) placed at array boundaries so the main loop never needs to check for edge cases explicitly.

Question 3

In the context of recursion, what causes a stack overflow?

Accepted Answer

Infinite or excessively deep recursive calls that exhaust call stack memory

Answer

Each recursive call pushes a frame onto the call stack; without a reachable base case or with very deep recursion, memory is exhausted.

Question 4

Which traversal visits a binary tree's nodes in ascending order when the tree is a BST?

Accepted Answer

In-order

Answer

In-order traversal (left → root → right) visits BST nodes in sorted ascending order.

Question 5

What is the purpose of a 'two-pointer' technique in array problems?

Accepted Answer

To reduce time complexity by maintaining two indices that move toward each other

Answer

Two pointers placed at opposite ends (or at specific offsets) allow many array problems to be solved in O(n) instead of O(n²).

Epic Skills Assessment Practice Test