#line 1 "test/aoj/2891/main.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2891"
#include <iostream>
#line 2 "Mylib/Graph/GraphUtils/decompose_pseudotree.cpp"
#include <queue>
#include <vector>
#line 4 "Mylib/Graph/Template/graph.cpp"
namespace haar_lib {
template <typename T>
struct edge {
int from, to;
T cost;
int index = -1;
edge() {}
edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
edge(int from, int to, T cost, int index) : from(from), to(to), cost(cost), index(index) {}
};
template <typename T>
struct graph {
using weight_type = T;
using edge_type = edge<T>;
std::vector<std::vector<edge<T>>> data;
auto& operator[](size_t i) { return data[i]; }
const auto& operator[](size_t i) const { return data[i]; }
auto begin() const { return data.begin(); }
auto end() const { return data.end(); }
graph() {}
graph(int N) : data(N) {}
bool empty() const { return data.empty(); }
int size() const { return data.size(); }
void add_edge(int i, int j, T w, int index = -1) {
data[i].emplace_back(i, j, w, index);
}
void add_undirected(int i, int j, T w, int index = -1) {
add_edge(i, j, w, index);
add_edge(j, i, w, index);
}
template <size_t I, bool DIRECTED = true, bool WEIGHTED = true>
void read(int M) {
for (int i = 0; i < M; ++i) {
int u, v;
std::cin >> u >> v;
u -= I;
v -= I;
T w = 1;
if (WEIGHTED) std::cin >> w;
if (DIRECTED)
add_edge(u, v, w, i);
else
add_undirected(u, v, w, i);
}
}
};
template <typename T>
using tree = graph<T>;
} // namespace haar_lib
#line 5 "Mylib/Graph/GraphUtils/decompose_pseudotree.cpp"
namespace haar_lib {
template <typename T>
class pseudo_tree {
int n_;
std::vector<bool> in_loop_;
std::vector<int> group_;
void dfs(int cur, int par, const graph<T> &g) {
group_[cur] = group_[par];
for (auto &e : g[cur]) {
if (e.to == par) continue;
dfs(e.to, cur, g);
}
}
public:
pseudo_tree() {}
pseudo_tree(const graph<T> &g) : n_(g.size()), in_loop_(n_, true), group_(n_) {
std::vector<int> indeg(n_);
std::vector<bool> visited(n_);
std::queue<int> q;
for (int i = 0; i < n_; ++i) {
for (auto &e : g[i]) {
++indeg[e.to];
}
}
for (int i = 0; i < n_; ++i) {
if (indeg[i] == 1) {
q.push(i);
}
}
while (not q.empty()) {
int cur = q.front();
q.pop();
in_loop_[cur] = false;
if (visited[cur]) continue;
visited[cur] = true;
for (auto &e : g[cur]) {
if (not visited[e.to]) {
--indeg[e.to];
if (indeg[e.to] == 1) {
q.push(e.to);
}
}
}
}
for (int i = 0; i < n_; ++i) {
if (in_loop_[i]) {
group_[i] = i;
for (auto &e : g[i]) {
if (not in_loop_[e.to]) {
dfs(e.to, i, g);
}
}
}
}
}
bool in_loop(int i) const { return in_loop_[i]; }
int group(int i) const { return group_[i]; }
};
} // namespace haar_lib
#line 2 "Mylib/IO/input_tuples.cpp"
#include <initializer_list>
#line 4 "Mylib/IO/input_tuples.cpp"
#include <tuple>
#include <utility>
#line 6 "Mylib/IO/input_tuple.cpp"
namespace haar_lib {
template <typename T, size_t... I>
static void input_tuple_helper(std::istream &s, T &val, std::index_sequence<I...>) {
(void) std::initializer_list<int>{(void(s >> std::get<I>(val)), 0)...};
}
template <typename T, typename U>
std::istream &operator>>(std::istream &s, std::pair<T, U> &value) {
s >> value.first >> value.second;
return s;
}
template <typename... Args>
std::istream &operator>>(std::istream &s, std::tuple<Args...> &value) {
input_tuple_helper(s, value, std::make_index_sequence<sizeof...(Args)>());
return s;
}
} // namespace haar_lib
#line 8 "Mylib/IO/input_tuples.cpp"
namespace haar_lib {
template <typename... Args>
class InputTuples {
struct iter {
using value_type = std::tuple<Args...>;
value_type value;
bool fetched = false;
int N, c = 0;
value_type operator*() {
if (not fetched) {
std::cin >> value;
}
return value;
}
void operator++() {
++c;
fetched = false;
}
bool operator!=(iter &) const {
return c < N;
}
iter(int N) : N(N) {}
};
int N;
public:
InputTuples(int N) : N(N) {}
iter begin() const { return iter(N); }
iter end() const { return iter(N); }
};
template <typename... Args>
auto input_tuples(int N) {
return InputTuples<Args...>(N);
}
} // namespace haar_lib
#line 7 "test/aoj/2891/main.test.cpp"
namespace hl = haar_lib;
int main() {
int N;
std::cin >> N;
hl::graph<int> g(N);
g.read<1, false, false>(N);
auto res = hl::pseudo_tree<int>(g);
int Q;
std::cin >> Q;
for (auto [a, b] : hl::input_tuples<int, int>(Q)) {
--a, --b;
if (res.in_loop(a) and res.in_loop(b)) {
std::cout << 2 << "\n";
} else {
std::cout << 1 << "\n";
}
}
return 0;
}
test/aoj/2891/main.test.cpp
Basic graph
(Mylib/Graph/Template/graph.cpp)