AP Computer Science A Resource

Algorithms practice guide

A connected AP Computer Science A algorithm map for searching, sorting, recursion, array/list processing, and String manipulation.

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Study Snapshot

AP unit

Units 2 and 4

Exam use

Search, sort, recursion, array/list processing, and runtime reasoning

Study time

60-75 min

Resource Navigator

Move through AP Computer Science A by skill

Open FRQ Heat Map

Step 1StringsString APIs, loops, tracing, and FRQ helpers Step 2ArraysArray creation, indexing, traversal, mutation, algorithms, and 2D arrays Step 3ArrayListDynamic lists, removal loops, object collections, and FRQ data processing Step 4AlgorithmsSearch, sort, recursion, array/list processing, and runtime reasoning

Best used when

Students preparing for mixed-topic MCQs and FRQs where algorithm patterns are combined.

Linear search works on unsorted data

Binary search requires sorted data

Selection and insertion sort are O(n^2)

Searching

Search questions test loop control, return values, and assumptions about the data.

Linear search checks each item until a match is found.

Binary search repeatedly halves a sorted search space.

Return -1 or false only after the search has fully failed.

Trace low, high, and mid carefully for binary search.

for (int i = 0; i < values.length; i++) {
  if (values[i] == target) {
    return i;
  }
}
return -1;

Sorting

AP Computer Science A expects students to recognize selection sort, insertion sort, and merge sort behavior.

Selection sort repeatedly chooses the next smallest value.

Insertion sort inserts each item into the sorted left side.

Merge sort divides, sorts, and merges.

Compare algorithms by trace behavior, not only by names.

Recursion and Processing

Recursive algorithms need a base case, a smaller call, and a meaningful return path.

Every recursive method needs a reachable base case.

The recursive call should move toward that base case.

Array and String algorithms often combine traversal with accumulation.

Runtime reasoning helps students compare simple loops, nested loops, and divide-and-conquer methods.

public static int sum(int n) {
  if (n == 0) {
    return 0;
  }
  return n + sum(n - 1);
}

Practice checklist

Use these prompts as a short self-check before moving back into FRQs or class assignments.

Trace binary search on a sorted array and record low, mid, and high each pass.

Write selection sort for an int array.

Write a recursive method that counts down by 2.

Compare a nested-loop algorithm with a single-loop algorithm using Big-O language.

For practice use only.

AP Computer Science A Algorithms Hard MCQ Practice

Practice hard AP Computer Science A searching, sorting, loop-boundary tracing, comparison counts, algorithm correctness, runtime intuition, and array/list mutation.

Question 1 of 25

Answered 0 of 25

Choose one answer.

What value is returned by search(data, 4)?

public static int search(int[] data, int target) {
  for (int i = 0; i < data.length; i++) {
    if (data[i] == target) {
      return i;
    }
  }
  return -1;
}

int[] data = {4, 2, 4, 1};

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