Lesson 1

Array Traversal Exploration with Gloria in C++


Welcome to a delightful lesson on array traversal! Today, we invite you to join an endearing bunny named Gloria on an intricate quest. Gloria has a soft spot for number games, especially when they involve hopping between arrays. Our goal on this exciting journey is to assist Gloria through her escapade and identify the maximum value she encounters along the way. Are you ready to embark on this adventure?

Task Statement

Gloria's quest unfolds with two arrays, both brimming with non-negative integers. Starting at the first element of arrayA, she leaps to arrayB based on the index she discovers in arrayA. She then bounces back to arrayA according to the index she stumbles upon in arrayB. Gloria repeats these hops until she returns to where she started in arrayA. What an adventure!

Your challenge is to craft a C++ function that aids Gloria on her trip. The function will take two arrays of integers as inputs, representing arrayA and arrayB. The objective is to find the highest value from arrayB that Gloria jumps to during her voyage.

It is guaranteed that at some point Gloria returns to the starting position.


If arrayA = {2, 4, 3, 1, 6} and arrayB = {4, 0, 3, 2, 0}, the output should be 3.

In this scenario, Gloria starts from the first element of arrayA, which is 2. Then, she jumps to arrayB at index 2, where she discovers 3. She then bounces back to arrayA at index 3, where she arrives at 1. From there, she leaps back to arrayB at index 1, stumbling upon a 0. Finally, she bounces back to arrayA at index 0, the location where she started her adventure. Hence, she stops here. During this journey, she encountered the highest value 3 from arrayB.

Solution Building: Step 1 - Initialization

Before we make headway with our code, let's kickstart with the initialization of variables. Let indexA and indexB denote the last positions of Gloria in arrayA and arrayB, respectively. We will also use max_value for tracking the highest value encountered in arrayB. Her quest starts from arrayA, so we also maintain a Boolean flag in_arrayA.

1int indexA = 0; 2int indexB = -1; 3bool in_arrayA = true; 4int max_value = INT_MIN;
Solution Building: Step 2 - Array Hopping

Our assistant for Gloria’s hopping challenge will be a while loop! This keeps iterating until Gloria returns to her starting position in arrayA.

If Gloria is in arrayA, we check if the value in arrayB where she is going to land is greater than max_value and update max_value if it is. We also switch Gloria's position to the other array in each iteration.

1while (true) { 2 if (in_arrayA) { 3 indexB = arrayA[indexA]; 4 if (arrayB[indexB] > max_value) { 5 max_value = arrayB[indexB]; 6 } 7 } else { 8 indexA = arrayB[indexB]; 9 if (indexA == 0) { 10 return max_value; 11 } 12 } 13 in_arrayA = !in_arrayA; 14}
Final Function

Collecting all the pieces together, here’s our ultimate function:

1#include <iostream> 2#include <climits> // For INT_MIN 3#include <vector> 4 5int solution(std::vector<int> arrayA, std::vector<int> arrayB, int sizeA, int sizeB) { 6 int indexA = 0; 7 int indexB = -1; 8 bool in_arrayA = true; 9 int max_value = INT_MIN; 10 11 while (true) { 12 if (in_arrayA) { 13 indexB = arrayA[indexA]; 14 if (arrayB[indexB] > max_value) { 15 max_value = arrayB[indexB]; 16 } 17 } else { 18 indexA = arrayB[indexB]; 19 if (indexA == 0) { 20 return max_value; 21 } 22 } 23 in_arrayA = !in_arrayA; 24 } 25} 26 27int main() { 28 std::vector<int> arrayA = {2, 4, 3, 1, 6}; 29 std::vector<int> arrayB = {4, 0, 3, 2, 0}; 30 int sizeA = arrayA.size(); 31 int sizeB = arrayB.size(); 32 33 std::cout << "Maximum value encountered in arrayB: " << solution(arrayA, arrayB, sizeA, sizeB) << std::endl; 34 35 return 0; 36}
Lesson Summary

Heartiest congratulations on guiding Gloria through her array-hopping adventure. Not only have you heightened Gloria's joy, but you've also skillfully solved a complex task. You've deftly handled arrays, tracked indices, and made careful use of conditional statements.

This experience should empower you to take on more complex coding challenges. Keep practicing, keep exploring, and keep growing. Happy coding!

Enjoy this lesson? Now it's time to practice with Cosmo!

Practice is how you turn knowledge into actual skills.