#include <cstdio>
#include <vector>
#include "solution.cpp"

static int failures = 0;
#define CHECK(cond, name) do { if (cond) std::printf("ok   %s\n", name); \
    else { std::printf("FAIL %s (line %d)\n", name, __LINE__); ++failures; } } while (0)

static Node* build(const std::vector<int>& v) {
    Node* head = nullptr; Node** tail = &head;
    for (int x : v) { *tail = new Node{x, nullptr}; tail = &(*tail)->next; }
    return head;
}
static std::vector<int> to_vec(Node* h, size_t limit = 1000) {
    std::vector<int> r; while (h && r.size() < limit) { r.push_back(h->value); h = h->next; } return r;
}
static void destroy(Node* h) { while (h) { Node* n = h->next; delete h; h = n; } }

int main() {
    // reverse
    {
        Node* h = build({1, 2, 3, 4, 5});
        Node* r = reverse_list(h);
        CHECK(to_vec(r) == std::vector<int>({5, 4, 3, 2, 1}), "reverse [1..5] -> [5..1]");
        destroy(r);
    }
    {
        Node* h = build({42});
        Node* r = reverse_list(h);
        CHECK(r && r->value == 42 && r->next == nullptr, "reverse одного узла");
        destroy(r);
    }
    CHECK(reverse_list(nullptr) == nullptr, "reverse пустого списка == nullptr");
    {
        Node* h = build({7, 8});
        Node* r = reverse_list(h);
        CHECK(to_vec(r) == std::vector<int>({8, 7}), "reverse двух узлов");
        destroy(r);
    }

    // middle
    {
        Node* h = build({1, 2, 3, 4, 5, 6});
        Node* m = find_middle(h);
        CHECK(m && m->value == 4, "middle чётного [1..6] == 4 (второй из двух средних)");
        destroy(h);
    }
    {
        Node* h = build({1, 2, 3, 4, 5});
        Node* m = find_middle(h);
        CHECK(m && m->value == 3, "middle нечётного [1..5] == 3");
        destroy(h);
    }
    {
        Node* h = build({9});
        CHECK(find_middle(h) && find_middle(h)->value == 9, "middle одного узла == 9");
        destroy(h);
    }
    CHECK(find_middle(nullptr) == nullptr, "middle пустого списка == nullptr");

    // cycle
    {
        Node* h = build({1, 2, 3, 4});
        CHECK(!has_cycle(h), "has_cycle(без цикла) == false");
        destroy(h);
    }
    {
        Node* h = build({1, 2, 3, 4, 5});
        Node* third = h->next->next;
        Node* last = h; while (last->next) last = last->next;
        last->next = third;                       // цикл 3->4->5->3
        CHECK(has_cycle(h), "has_cycle(цикл внутри) == true");
        last->next = nullptr;
        destroy(h);
    }
    {
        Node* h = build({1, 2});
        Node* last = h->next; last->next = h;     // цикл на всю длину
        CHECK(has_cycle(h), "has_cycle(цикл на всю длину) == true");
        last->next = nullptr;
        destroy(h);
    }
    {
        Node* one = new Node{5, nullptr};
        one->next = one;
        CHECK(has_cycle(one), "has_cycle(сам на себя) == true");
        one->next = nullptr;
        delete one;
    }
    CHECK(!has_cycle(nullptr), "has_cycle(nullptr) == false");

    std::printf(failures ? "\nFAILURES: %d\n" : "\nALL PASS\n", failures);
    return failures ? 1 : 0;
}