All Flashcards

What are the general steps for writing a recursive function?

Identify the base case(s). 2. Define the recursive call to solve a smaller subproblem. 3. Ensure the recursive call moves towards the base case.

What are the steps of the binary search algorithm?

Find the middle element. 2. Compare the target to the middle element. 3. If target equals middle, return index. 4. If target is less than middle, search the left half. 5. If target is greater than middle, search the right half. 6. Repeat until found or search space is empty.

What are the main steps of the merge sort algorithm?

Divide the array into two halves. 2. Recursively sort the two halves. 3. Merge the sorted halves.

What does the following code output?

java
public int factorial(int n) {
  if (n == 0) {
    return 1;
  } else {
    return n * factorial(n-1);
  }
}
System.out.println(factorial(4));

Identify the error in the following code:

java
public int factorial(int n) {
  return n * factorial(n-1);
}

Missing base case, which will cause a stack overflow error.

What does the following code output?

java
public void traverseArray(int[] array, int index) {
  if (index == array.length) {
    return;
  }
  System.out.println(array[index]);
  traverseArray(array, index + 1);
}
int[] arr = {1, 2, 3};
traverseArray(arr, 0);

1 2 3

What does the following code output?

java
public int binarySearch(int[] array, int target, int low, int high) {
  if (low > high) {
    return -1;
  }
  int mid = (low + high) / 2;
  if (array[mid] == target) {
    return mid;
  } else if (target < array[mid]) {
    return binarySearch(array, target, low, mid - 1);
  } else {
    return binarySearch(array, target, mid + 1, high);
  }
}
int[] arr = {2, 4, 6, 8, 10};
System.out.println(binarySearch(arr, 6, 0, arr.length - 1));

Identify the potential issue in the following binary search code:

java
int mid = (low + high) / 2;

Integer overflow can occur if low + high exceeds the maximum integer value. Using mid = low + (high - low) / 2; is a safer alternative.

Predict the output of the following code:

java
public int mystery(int n) {
  if (n <= 0) {
    return 0;
  } else {
    return n + mystery(n - 2);
  }
}
System.out.println(mystery(5));

What is the output of the following code?

java
public int recursiveMethod(int num) {
 if (num == 0)
 return 1;
 else
 return num * recursiveMethod(num - 1);
}
System.out.println(recursiveMethod(3));

What is the output of the following code?

java
public int method(int num) {
 if (num == 5)
 return 5;
 else
 return num + method(num + 1);
}
System.out.println(method(2));

What is the output of the following code?

java
public int method(int num) {
 if (num == 0)
 return 0;
 else
 return 1 + method(num / 2);
}
System.out.println(method(8));

What is the output of the following code?

java
public int method(int num) {
 if (num == 0)
 return 0;
 else
 return 1 + method(num - 1);
}
System.out.println(method(4));

What is the definition of Recursion?

A method of solving a problem where the solution depends on solutions to smaller instances of the same problem. A function calls itself with a smaller version of the original problem.

What is the definition of Base Case?

A condition in a recursive method that terminates the recursive calls and provides a direct solution.

What is the definition of Recursive Call?

When a function calls itself with a modified version of the original problem, usually after checking the base case.

What is the definition of Binary Search?

A search algorithm that finds the position of a target value within a sorted array by repeatedly dividing the search interval in half.

What is the definition of Merge Sort?

An efficient, general-purpose, comparison-based sorting algorithm that divides an array into two halves, sorts each half, and then merges the sorted halves back together.