Here is my c++ solution

int workbook(int n, int k, vector arr) { vector> pages; int specialCount = 0;

for (int chapter = 0; chapter < n; chapter++) {
    int problems = arr[chapter];
    int problemNum = 1;

    while (problemNum <= problems) {
        int end = min(problemNum + k - 1, problems);
        vector<int> page;

        for (int i = problemNum; i <= end; i++) {
            page.push_back(i);
        }

        pages.push_back(page);
        problemNum = end + 1;
    }
}


for (int i = 0; i < pages.size(); i++) {
    int pageNumber = i + 1;
    for (int j=0;j<pages[i].size();j++) {
        if (pages[i][j] == pageNumber) {
            specialCount++;
        }
    }
}

return specialCount;

}