Embercode: AI-powered software engineer course

1. Predict the output of this program. ``

cpp
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

void rotateRight(vector<int>& a, int k) {
    int n = static_cast<int>(a.size());
    if (n == 0) {
        return;
    }
    k %= n;
    reverse(a.begin(), a.end());
    reverse(a.begin(), a.begin() + k);
    reverse(a.begin() + k, a.end());
}

int main() {
    vector<int> a = {2, 4, 6, 8, 10, 12};
    rotateRight(a, 8);
    for (int x : a) {
        cout << x << " ";
    }
    cout << "\n";
}

`` What does it print?

4 6 8 10 12 28 10 12 2 4 610 12 2 4 6 82 4 6 8 10 12

2. Predict the output of this program. It applies the updates to a difference array and then runs the total. ``

cpp
#include <iostream>
#include <vector>
using namespace std;

int main() {
    vector<int> diff(6, 0);
    diff[0] += 3;
    diff[3] -= 3;
    diff[2] += 1;
    diff[5] -= 1;
    int run = 0;
    for (int i = 0; i < 5; ++i) {
        run += diff[i];
        cout << run << " ";
    }
    cout << "\n";
}

`` What does it print?

3 3 4 1 13 3 4 4 13 3 1 1 13 3 4 1 0

3. Reverse the whole array 1 2 3 4 5 with reverse(a.begin(), a.end()). Write the five values in the order they read afterwards, separated by spaces.

Type your answer.

4. To add v to every index from l to r in a difference array, the second write is diff[____] -= v. Write the index as an expression in r.

Type your answer.

5. What does the line k %= n do at the start of rotateRight? ``

cpp
int n = static_cast<int>(a.size());
if (n == 0) {
    return;
}
k %= n;

``

It sorts the array by kIt keeps k between 0 and n - 1, so the iterators stay inside the arrayIt doubles k when k is smaller than nIt removes the last k values from the array

Rotation and differences