medians of n sorted vectors

#include <iostream>
#include <iomanip>

int less(const int* a, int value, int size, bool flag) {
    int l = -1, r = size;
    while (l < r - 1) {
        int m = (l + r) / 2;
        if (a[m] < value || a[m] == value && flag) {
            l = m;
        } else {
            r = m;
        }
    }
    return r;
}

int medianInFirst(const int* a, const int* b, int size, int index) {
    int i = -1, jmin, jmax;
    int l = 0, r = size;
    while (1) {
        if (i == (l + r) / 2) {
            return -1;
        }
        i = (l + r) / 2;
        jmin = less(b, a[i], size, 0) + less(a, a[i], size, 0);
        jmax = less(b, a[i], size, 1) + less(a, a[i], size, 1) - 1;
        if (jmin <= index && jmax >= index) {
            return i;
        }
        if (jmax < index) {
            l = i;
        } else {
            r = i;
        }
    }
}

double median(const int* a, const int* b, int size) {
    int medians[2];
    for (int i = 0; i < 2; ++i) {
        int temp = medianInFirst(a, b, size, size - 1 + i);
        if (temp == -1) {
            temp = medianInFirst(b, a, size, size - 1 + i);
            medians[i] = b[temp];
        } else {
            medians[i] = a[temp];
        }
    }
    return static_cast<double>(medians[0] + medians[1]) / 2;
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(5);
    std::cin.tie(nullptr);
    int n, m;
    std::cin >> n >> m;
    int** vecs = new int*[n];
    for (int i = 0; i < n; ++i) {
        vecs[i] = new int[m];
        for (int j = 0; j < m; ++j) {
            std::cin >> vecs[i][j];
        }
    }
    for (int i = 0; i < n - 1; ++i) {
        for (int j = i + 1; j < n; ++j) {
            std::cout << median(vecs[i], vecs[j], m) << "\n";
        }
    }
    for (int i = 0; i < n; ++i) {
        delete[] vecs[i];
    }
    delete[] vecs;
}