### All AP Computer Science A Resources

## Example Questions

### Example Question #1 : Sorting

Which of the following statements explains insertion sort?

**Possible Answers:**

It removes one element from the list, finds where it should be located, and inserts it in that position until no more elements remain.

The list is iterated through multiple times until it finds the desired first number, then repeats the process for all numbers.

All numbers less than the average are inserted on the left, and the rest is inserted at the right. The process is then repeated for the left and right side until all numbers are sorted.

The list is broken apart into smaller lists that are sorted and merged back together.

None of these are insertion sort.

**Correct answer:**

It removes one element from the list, finds where it should be located, and inserts it in that position until no more elements remain.

Insertion sort removes an element from a list, checks the values adjacent to it to see if it is greater or smaller, until it finds the position where the number to the left is smaller and the number to the right is larger and places it there.

### Example Question #1 : Sorting

{1, 9, 5, 4, 2, 0, 4}

What would the set of numbers look like after four iterations of Insertion Sort?

**Possible Answers:**

{1, 4, 4, 9, 5, 2, 0}

{1, 4, 5, 9, 2, 0, 4}

{1, 4, 4, 5, 9, 2, 0}

{1, 9, 4, 5, 2, 0, 4}

{1, 4, 9, 5, 2, 0, 4}

**Correct answer:**

{1, 4, 5, 9, 2, 0, 4}

Insertion Sort is a sorting algorithm that starts at the beginning of an array and with each iteration of the array it sorts the values from smallest to largest.

Therefore, after four iterations of Insertion Sort, the first four numbers will be in order from smallest to largest.

### Example Question #1 : Sorting

Which of the following do we consider when choosing a sorting algorithm to use?

I. Space efficiency

II. Run time efficiency

III. Array size

IV. Implementation language

**Possible Answers:**

II, III, IV

I, II, III, IV

I, II

II, IV

I, II, III

**Correct answer:**

I, II, III, IV

All of the choices are important when choosing a sorting algorithm. Space and time complexity are the characteristics by which we measure the performance of an algorithm. the array size directly affects the performance of an algorithm. In addition, the language which the algorithm is written in can also affect the performance (for example, insertion sort may run faster in one language versus another, due the way the language was designed).

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