coding interview preparation coursera week 3 quiz answers

Knowledge check: Sorting and searching

1. Given an array of 6 numbers -> 6, 8, 19, 48, 9, 90 and applying a selection sort. How many swaps must occur before the array is sorted?

  • 4
  • 2
  • 6

2. Given an array of numbers and a target value, using a loop, what is the worst-case time complexity to check if the number is present in the array?

  • O(log n)
  • O(n)
  • O(1)

3. A binary search can only be performed on a sorted dataset.

  • True
  • False

4. Given the following snippet of pseudocode:

array = []

n = 4

FOR i = 0 TO n:

FOR j = 0 TO n:

array.add(i*j)

What is the space complexity of this problem?

  • O(n)
  • O(n^2)
  • O(log n)

5. What advantage is there to changing element location using an in-place swap?

  • It reduces the amount of space taken by removing the need to create another variable in memory.
  • It reduces the time taken to complete an algorithm through lowering the time complexity.
  • It is a memory feature that allows many variables to reference the same memory location.

Knowledge check: Working with algorithms

6. What is memoization?

  • It is a practice of only computing what is in the cache in place of expensive memory calls.
  • It is a process of retaining the results from a computation so that they can be reused rather than recalculating a result
  • It is an example of divide and conquer.

7. The practice of breaking a problem into a set of overlapping subproblems is referred to as:

  • Divide and conquer
  • Dynamic programming
  • Memoization

8. Quicksort is an example of divide and conquer?

  • True
  • False

Shuffle Q/A 1

9. Examine the following problem:

A bank robber has entered a bank vault and sees 3 stacks of precious bars: Gold, silver and platinum. The gold weighs 6kg and is valued at 60 dollars. The silver weighs 1 kg and is valued at 5 dollars. And the platinum weighs 10kg and is valued at 110 dollars. The robber can only carry 38kg. What is the optimal combination of items to take? Your solution is to fill the bag with as many platinum bars as possible before moving to the gold and then the silver. What type of approach best describes this solution?

  • Dynamic programming
  • Greedy approach
  • Graph approach

10. Why is a base case crucial when designing recursive solutions?

  • It is used to ensure that the input diminishes at each call.
  • The algorithm needs to know the shape of the minimum case so it can model the solution from it.
  • Without it the function would go on forever.
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