結果

問題 No.2301 Namorientation
コンテスト
ユーザー Daylight
提出日時 2023-05-12 22:31:53
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 970 ms / 3,000 ms
コード長 5,115 bytes
コンパイル時間 2,598 ms
コンパイル使用メモリ 219,872 KB
最終ジャッジ日時 2025-02-12 23:16:50
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 30
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>

using namespace std;
#define SZ(x) (int) (x).size()
#define REP(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, b) for(auto i = (a); i < (b); i++)
#define For(i, a, b, c) \
	for(auto i = (a); i != (b); i += (c))
#define REPR(i, n) for(auto i = (n) -1; i >= 0; i--)
#define ALL(s) (s).begin(), (s).end()
#define so(V) sort(ALL(V))
#define rev(V) reverse(ALL(V))
#define uni(v) v.erase(unique(ALL(v)), (v).end())
#define eb emplace_back

typedef unsigned long long ull;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> PI;
typedef pair<ll, ll> PL;
const double EPS = 1e-6;
const int MOD = 1e9 + 7;
const int INF = (1 << 30);
const ll LINF = 1e18;
const double math_PI = acos(-1);

template<typename T>
vector<T> make_v(size_t a) {
	return vector<T>(a);
}

template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
	return vector<decltype(make_v<T>(ts...))>(
		a, make_v<T>(ts...));
}

template<typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(
	T& t, const V& v) {
	t = v;
}

template<typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(
	T& t, const V& v) {
	for(auto& e: t) fill_v(e, v);
}

template<class T>
bool chmax(T& a, const T& b) {
	if(a < b) {
		a = b;
		return true;
	}
	return false;
}

template<class T>
bool chmin(T& a, const T& b) {
	if(a > b) {
		a = b;
		return true;
	}
	return false;
}

template<typename S, typename T>
istream& operator>>(istream& is, pair<S, T>& p) {
	cin >> p.first >> p.second;
	return is;
}

template<typename T>
istream& operator>>(istream& is, vector<T>& vec) {
	for(T& x: vec) is >> x;
	return is;
}

template<typename T>
string join(vector<T>& vec, string splitter) {
	stringstream ss;
	REP(i, SZ(vec)) {
		if(i != 0) ss << splitter;
		ss << vec[i];
	}
	return ss.str();
}

template<typename T>
ostream& operator<<(ostream& os, vector<T>& vec) {
	os << join(vec, " ");
	return os;
}
template<class T = ll>
struct Edge {
public:
	int from, to;
	T cost;
	Edge() {
	}
	Edge(int _from, int _to, T _cost) {
		from = _from;
		to = _to;
		cost = _cost;
	}
};
template<class T = ll>
using Edges = vector<Edge<T>>;
template<class T = ll>
using Graph = vector<Edges<T>>;
vi cycle_detection(Graph<>& G) {
	int N = SZ(G);
	vi cycle;
	vb visited(N);
	vb seen(N);
	auto dfs = [&](auto f, int cur, int pre = -1) -> int {
		if(seen[cur]) {
			return cur;
		}
		seen[cur] = true;
		for(Edge e: G[cur]) {
			if(e.to == pre) continue;
			if(visited[e.to]) continue;
			int begin = f(f, e.to, cur);
			if(begin == -2) {
				visited[cur] = true;
				return -2;
			}
			if(begin == -1) continue;
			if(begin == cur) {
				cycle.push_back(cur);
				visited[cur] = true;
				return -2;
			}
			cycle.push_back(cur);
			visited[cur] = true;
			return begin;
		}
		visited[cur] = true;
		return -1;
	};
	REP(i, N) {
		if(!cycle.empty()) break;
		if(visited[i]) continue;
		dfs(dfs, i);
	}
	if(cycle.empty()) {
		return vi();
	}
	rev(cycle);
	vi C(N, -1);
	REP(i, SZ(cycle)) {
		C[cycle[i]] = i;
	}
	int ind = 0;
	vi ret;
	using P = pair<int, int>;
	set<P> S;
	while(ind != -1) {
		int v = cycle[ind];
		ret.push_back(v);
		S.insert({ ind, SZ(ret) - 1 });
		int next = -1;
		int pre = -1;
		for(Edge e: G[v]) {
			int n = C[e.to];
			if(n == -1) continue;
			if(n < ind) {
				auto [a, b] = *S.lower_bound({ n, 0 });
				if(a != n) continue;
				chmax(pre, b);
			}
			chmax(next, n);
		}
		if(pre != -1) {
			vi new_ret;
			FOR(i, pre, SZ(ret)) {
				new_ret.push_back(ret[i]);
			}
			ret = new_ret;
			return ret;
		}
		ind = next;
	}
	return ret;
}

int main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int N;
	cin >> N;
	Graph<> G(N);
	map<PI, int> M;
	REP(i, N) {
		int A, B;
		cin >> A >> B;
		A--;
		B--;
		G[A].eb(A, B, i + 1);
		G[B].eb(B, A, -i - 1);
		M[{ A, B }] = i + 1;
		M[{ B, A }] = -1 - i;
	}
	vi to(N, -1);
	vi ans(N, -1);
	auto dfs2 = [&](auto f, int cur, int pre) -> void {
		int m = M[{ pre, cur }];
		if(m > 0)
			ans[m - 1] = 0;
		else
			ans[-m - 1] = 1;
		for(auto e: G[cur]) {
			if(e.to == pre) continue;
			f(f, e.to, cur);
		}
	};
	bool found = false;
	auto dfs = [&](auto f, int cur, int pre) -> void {
		if(found) return;
		if(to[cur] != -1) {
			int c = cur;
			int p = pre;
			int m = M[{ p, c }];
			if(m > 0)
				ans[m - 1] = 1;
			else
				ans[-m - 1] = 0;
			for(auto e: G[c]) {
				if(e.to != to[c] && e.to != p) {
					dfs2(dfs2, e.to, c);
				}
			}
			p = c;
			c = to[c];
			while(c != cur) {
				m = M[{ p, c }];
				if(m > 0)
					ans[m - 1] = 1;
				else
					ans[-m - 1] = 0;
				for(auto e: G[c]) {
					if(e.to != to[c] && e.to != p) {
						dfs2(dfs2, e.to, c);
					}
				}
				p = c;
				c = to[c];
			}
			found = true;
			return;
		}
		for(auto e: G[cur]) {
			if(e.to == pre) continue;
			to[e.from] = e.to;
			f(f, e.to, e.from);
			to[e.from] = -1;
		}
	};
	dfs(dfs, 0, -1);
	REP(i, N) {
		if(ans[i] == 1) {
			cout << "->" << endl;
		} else if(ans[i] == 0) {
			cout << "<-" << endl;
		}
	}
	return 0;
}
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