23401 quick and merge sort

#include <iostream>
#include <vector>
#include <string>

using namespace std;

int quickSortComparisons = 0;
int mergeSortComparisons = 0;

struct Student {
    char name[50];
    double grade;
};

// --- MERGE SORT (REVERSE) ---
void mergeReverse(vector<int> &arr, int low, int mid, int high) {
    int n1 = mid - low + 1;
    int n2 = high - mid;
    vector<int> L(n1), R(n2);
    for (int i = 0; i < n1; i++) L[i] = arr[low + i];
    for (int j = 0; j < n2; j++) R[j] = arr[mid + 1 + j];

    int i = 0, j = 0, k = low;
    while (i < n1 && j < n2) {
        mergeSortComparisons++;
        if (L[i] >= R[j]) {
            arr[k++] = L[i++];
        } else {
            arr[k++] = R[j++];
        }
    }
    while (i < n1) arr[k++] = L[i++];
    while (j < n2) arr[k++] = R[j++];
}

void mergeSortReverse(vector<int> &arr, int low, int high) {
    if (low >= high) return;
    int mid = low + (high - low) / 2;
    mergeSortReverse(arr, low, mid);
    mergeSortReverse(arr, mid + 1, high);
    mergeReverse(arr, low, mid, high);
}

// --- QUICK SORT (REVERSE) ---
int partitionReverse(vector<int> &arr, int low, int high) {
    int pivot = arr[high];
    int i = low - 1;
    for (int j = low; j < high; j++) {
        quickSortComparisons++;
        if (arr[j] >= pivot) {
            i++;
            swap(arr[i], arr[j]);
        }
    }
    swap(arr[i + 1], arr[high]);
    return i + 1;
}

void quickSortReverse(vector<int> &arr, int low, int high) {
    if (low < high) {
        int partitionIndex = partitionReverse(arr, low, high);
        quickSortReverse(arr, low, partitionIndex - 1);
        quickSortReverse(arr, partitionIndex + 1, high);
    }
}

// --- MERGE SORT (STRINGS) ---
void mergeString(vector<string> &strArr, int low, int mid, int high) {
    int n1 = mid - low + 1;
    int n2 = high - mid;
    vector<string> L(n1), R(n2);
    for (int i = 0; i < n1; i++) L[i] = strArr[low + i];
    for (int j = 0; j < n2; j++) R[j] = strArr[mid + 1 + j];

    int i = 0, j = 0, k = low;
    while (i < n1 && j < n2) {
        if (L[i] <= R[j]) {
            // Азбучен ред
            strArr[k++] = L[i++];
        } else {
            strArr[k++] = R[j++];
        }
    }
    while (i < n1) strArr[k++] = L[i++];
    while (j < n2) strArr[k++] = R[j++];
}

void mergeSortString(vector<string> &strArr, int low, int high) {
    if (low >= high) return;
    int mid = low + (high - low) / 2;
    mergeSortString(strArr, low, mid);
    mergeSortString(strArr, mid + 1, high);
    mergeString(strArr, low, mid, high);
}


int partitionGrades(vector<double> &grades, int low, int high) {
    double pivot = grades[high];
    int i = (low - 1);
    for (int j = low; j < high; j++) {
        if (grades[j] <= pivot) {
            i++;
            swap(grades[i], grades[j]);
        }
    }
    swap(grades[i + 1], grades[high]);
    return (i + 1);
}

void quickSortGrades(vector<double> &grades, int low, int high) {
    if (low < high) {
        int pi = partitionGrades(grades, low, high);
        quickSortGrades(grades, low, pi - 1);
        quickSortGrades(grades, pi + 1, high);
    }
}

int main() {
    // 1
    cout << "Zad 1 - Broy i chisla: ";
    int n1;
    cin >> n1;
    vector<int> arr1;
    for (int i = 0; i < n1; i++) {
        int a;
        cin >> a;
        arr1.push_back(a);
    }
    mergeSortReverse(arr1, 0, n1 - 1);
    for (int x: arr1) cout << x << " ";
    cout << endl;
    // 2
    cout << "Zad 2 - Broy i chisla: ";
    int n2;
    cin >> n2;
    vector<int> arr2;
    for (int i = 0; i < n2; i++) {
        int a;
        cin >> a;
        arr2.push_back(a);
    }
    quickSortReverse(arr2, 0, n2 - 1);
    for (int x: arr2) cout << x << " ";
    cout << endl;
    // 3
    cout << "Zad 3 - Sravnenia: " << endl;
    cout << "Merge Sort Comparisons: " << mergeSortComparisons << endl;
    cout << "Quick Sort Comparisons: " << quickSortComparisons << endl;
    // 4
    cout << "Zad 4 - Broy i imena: ";
    int n4;
    cin >> n4;
    vector<string> names(n4);
    for (int i = 0; i < n4; i++) cin >> names[i];
    mergeSortString(names, 0, n4 - 1);
    for (string s: names) cout << s << " ";
    cout << endl;
    // 5
    cout << "Zad 5 - Broy i ocenki: ";
    int n5;
    cin >> n5;
    vector<double> grades(n5);
    for (int i = 0; i < n5; i++) cin >> grades[i];
    quickSortGrades(grades, 0, n5 - 1);
    for (double g: grades) cout << g << " ";
    cout << endl;
    //6
    cout << "Zad 6 - Broy i uchenici (ime uspeh): ";
    int n6;
    cin >> n6;
    vector<Student> students(n6);
    for (int i = 0; i < n6; i++) {
        cin >> students[i].name >> students[i].grade;
    }
    for (int i = 0; i < n6 - 1; i++) {
        int maxGrade = i;
        for (int j = i + 1; j < n6; j++) {
            if (students[j].grade > students[maxGrade].grade) {
                maxGrade = j;
            } else if (students[j].grade == students[maxGrade].grade) {
                int k = 0;
                while (students[j].name[k] != '\0' && students[j].name[k] == students[maxGrade].name[k]) k++;
                if (students[j].name[k] < students[maxGrade].name[k]) maxGrade = j;
            }
        }
        swap(students[i], students[maxGrade]);
    }
    for (int i = 0; i < n6; i++) {
        cout << students[i].name << " " << students[i].grade << endl;
    }

    return 0;
}