Module 4: Final project and assessment: Data structures and algorithms

Course quiz: Data structures and algorithms

Practice Assignment

1. You are developing a weather prediction system that needs to store daily temperature values for a week. Which of the following correctly declares an array to store daily temperatures?

  • int temperatures = new int[7];
  • int[] temperatures = int[7];
  • int[] temperatures = new int[7];
  • int temperatures[7] = new int();

2. You're tasked with developing a to-do list application that manages tasks using an ArrayList. Which method would you use to remove a task named "Buy Groceries"?

  • tasks.delete(“Buy Groceries”);
  • tasks.clear(“Buy Groceries”);
  • tasks.remove(“Buy Groceries”);
  • tasks.pop(“Buy Groceries”);

3. You need to find the index of the number 15 in a sorted array of integers. Given the sorted array int[] sortedArray = {1, 5, 10, 15, 20};, which of the following code snippets correctly performs a binary search for the number 15?

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4. Which code snippet correctly checks for balanced parentheses in the string "{[()]}" using a stack?

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5. What is the most efficient way to add a new node at the beginning of a singly linked list?

  • Set the new node’s next reference to the current head and update the head to the new node.
  • Traverse to the end of the list and then insert the node.
  • Traverse to the middle of the list and insert the node there.
  • Set the current tail’s next reference to the new node.

6. What is a characteristic of a doubly linked list that a singly linked list does not have?

  • Nodes contain references to the next node only.
  • Nodes are stored in contiguous memory locations.
  • Each node has two references: one to the next node and one to the previous node.

  • It can only be traversed in one direction.

7. In a HashMap map, you want to update the value associated with the key id only if the key already exists. Which method would you use?

  • map.containsKey(“id”, newValue);
  • map.update(“id”, newValue);
  • map.put(“id”, newValue);
  • *A:map.replace(“id”, newValue);

8. What does the assertEquals method do in JUnit?

  • Compares two integers.
  • Checks if a collection is empty.
  • Asserts that two values are equal.
  • Throws an exception.

9. Which sorting algorithm is not suitable for very large datasets due to its quadratic time complexity?

  • Merge Sort
  • Quick Sort
  • Insertion Sort
  • Heap Sort

10. How does Merge Sort operate?

  • It repeatedly selects the smallest element and moves it to the beginning.
  • It divides the array into halves, sorts each half, and then merges them.
  • It swaps adjacent elements if they are in the wrong order.
  • It partitions the array around a pivot element.

11. How can the worst-case scenario for Quick Sort be avoided?

  • Always choose the first element as a pivot.
  • Increase the size of the array.
  • Use randomization or the “median of three” strategy.
  • Use a recursive function with a higher depth.

12. In a sorted array of 1000 elements, how many comparisons would binary search take in the worst case?

  • 1
  • 10

  • 100
  • 1000

13. Which method is used to retrieve the greatest key less than or equal to the given key in a TreeMap?

  • map.floorEntry(K key);
  • map.ceilingEntry(K key);
  • map.lowerEntry(K key);
  • map.higherEntry(K key);

14. What is a key characteristic of a LinkedHashMap compared to a HashMap?

  • It maintains insertion order of elements.

  • It sorts elements in descending order.
  • It allows duplicate keys.
  • It does not permit null keys.

15. True or False: In a doubly linked list, theremoveFirst() method deletes the first node by setting the prev reference of the second node to null.

  • True
  • False

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