Помогите с С++! Надо как-то решить задачу с помощью бинарного поиска

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>

using Vector = std::vector<int>;

template <class Compare>
size_t ternarySearch(const Vector& v, Compare comp) {
    size_t l = 0, r = v.size() - 1;
    while (r - l > 2) {
        const size_t a = l + (r - l) / 3;
        const size_t b = r - (r - l) / 3;
        if (comp(v[a], v[b]))
            r = b;
        else
            l = a;
    }
    return std::min_element(v.cbegin() + l, v.cbegin() + r + 1, comp) - v.cbegin();
}

template <class Compare>
int binarySearch(const Vector& v, size_t l, size_t r, int value, Compare comp) {
    auto it = std::lower_bound(v.cbegin() + l, v.cbegin() + r, value, comp);
    return it == v.cbegin() + r || comp(value, *it) ? -1 : it - v.cbegin();
}

template <class Compare1, class Compare2>
void requestProc(const Vector& v, size_t m, Compare1 less, Compare2 greater) {
    const size_t idxExtremum = ternarySearch(v, greater);
    for (size_t i = 0; i < m; ++i) {
        int query;
        std::cin >> query;
        int pos = binarySearch(v, 0, idxExtremum, query, less);
        if (pos == -1)
            pos = binarySearch(v, idxExtremum, v.size(), query, greater);
        std::cout << pos << '\n';
    }
}

int main() {
    size_t n;
    std::cin >> n;
    Vector v(n);
    for (auto& item : v)
        std::cin >> item;
    size_t m;
    std::cin >> m;
    if (n > 1) {
        if (v[0] < v[1])
            requestProc(v, m, std::less<int>(), std::greater<int>());
        else
            requestProc(v, m, std::greater<int>(), std::less<int>());
    } else if (n == 1) {
        for (size_t i = 0; i < m; ++i) {
            int query;
            std::cin >> query;
            std::cout << (v[0] == query ? "0\n" : "-1\n");
        }
    } else {
        for (size_t i = 0; i < m; ++i)
            std::cout << "-1\n";
    }
    return 0;
}