結果

問題 No.2638 Initial fare
ユーザー AerenAeren
提出日時 2024-02-19 21:29:46
言語 C++23
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 186 ms / 2,000 ms
コード長 7,517 bytes
コンパイル時間 2,964 ms
コンパイル使用メモリ 273,584 KB
実行使用メモリ 64,728 KB
最終ジャッジ日時 2024-02-19 21:29:56
合計ジャッジ時間 6,791 ms
ジャッジサーバーID
（参考情報） 		judge13 / judge11
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
6,676 KB
testcase_01 AC 2 ms
6,676 KB
testcase_02 AC 1 ms
6,676 KB
testcase_03 AC 1 ms
6,676 KB
testcase_04 AC 132 ms
34,900 KB
testcase_05 AC 142 ms
35,812 KB
testcase_06 AC 1 ms
6,676 KB
testcase_07 AC 115 ms
36,192 KB
testcase_08 AC 84 ms
33,676 KB
testcase_09 AC 99 ms
36,128 KB
testcase_10 AC 102 ms
36,472 KB
testcase_11 AC 1 ms
6,676 KB
testcase_12 AC 124 ms
35,752 KB
testcase_13 AC 91 ms
32,740 KB
testcase_14 AC 110 ms
36,724 KB
testcase_15 AC 97 ms
36,380 KB
testcase_16 AC 2 ms
6,676 KB
testcase_17 AC 112 ms
35,888 KB
testcase_18 AC 101 ms
35,208 KB
testcase_19 AC 125 ms
39,276 KB
testcase_20 AC 124 ms
37,384 KB
testcase_21 AC 131 ms
40,872 KB
testcase_22 AC 2 ms
6,676 KB
testcase_23 AC 177 ms
64,728 KB
testcase_24 AC 176 ms
59,716 KB
testcase_25 AC 1 ms
6,676 KB
testcase_26 AC 186 ms
51,488 KB
testcase_27 AC 162 ms
60,624 KB
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ソースコード

diff # 

// #pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
// #include <x86intrin.h>
using namespace std;
#if __cplusplus >= 202002L
using namespace numbers;
#endif

template<class T>
struct graph{
	using Weight_t = T;
	struct Edge_t{
		int from, to;
		T cost;
	};
	int n;
	vector<Edge_t> edge;
	vector<vector<int>> adj;
	function<bool(int)> ignore;
	graph(int n = 1): n(n), adj(n){
		assert(n >= 1);
	}
	graph(const vector<vector<int>> &adj, bool undirected = true): n((int)adj.size()), adj(n){
		assert(n >= 1);
		if(undirected){
			for(auto u = 0; u < n; ++ u) for(auto v: adj[u]) if(u < v) link(u, v);
		}
		else for(auto u = 0; u < n; ++ u) for(auto v: adj[u]) orient(u, v);
	}
	graph(const vector<vector<pair<int, T>>> &adj, bool undirected = true): n((int)adj.size()), adj(n){
		assert(n >= 1);
		if(undirected){
			for(auto u = 0; u < n; ++ u) for(auto [v, w]: adj[u]) if(u < v) link(u, v, w);
		}
		else for(auto u = 0; u < n; ++ u) for(auto [v, w]: adj[u]) orient(u, v, w);
	}
	graph(int n, vector<array<int, 2>> &edge, bool undirected = true): n(n), adj(n){
		assert(n >= 1);
		for(auto [u, v]: edge) undirected ? link(u, v) : orient(u, v);
	}
	graph(int n, vector<tuple<int, int, T>> &edge, bool undirected = true): n(n), adj(n){
		assert(n >= 1);
		for(auto [u, v, w]: edge) undirected ? link(u, v, w) : orient(u, v, w);
	}
	int operator()(int u, int id) const{
		#ifdef LOCAL
		assert(0 <= id && id < (int)edge.size());
		assert(edge[id].from == u || edge[id].to == u);
		#endif
		return u ^ edge[id].from ^ edge[id].to;
	}
	int link(int u, int v, T w = {}){ // insert an undirected edge
		int id = (int)edge.size();
		adj[u].push_back(id), adj[v].push_back(id), edge.push_back({u, v, w});
		return id;
	}
	int orient(int u, int v, T w = {}){ // insert a directed edge
		int id = (int)edge.size();
		adj[u].push_back(id), edge.push_back({u, v, w});
		return id;
	}
	void clear(){
		for(auto [u, v, w]: edge){
			adj[u].clear();
			adj[v].clear();
		}
		edge.clear();
		ignore = {};
	}
	graph transposed() const{ // the transpose of the directed graph
		graph res(n);
		for(auto &e: edge) res.orient(e.to, e.from, e.cost);
		res.ignore = ignore;
		return res;
	}
	int degree(int u) const{ // the degree (outdegree if directed) of u (without the ignoration rule)
		return (int)adj[u].size();
	}
	// The adjacency list is sorted for each vertex.
	vector<vector<int>> get_adjacency_list() const{
		vector<vector<int>> res(n);
		for(auto u = 0; u < n; ++ u) for(auto id: adj[u]){
			if(ignore && ignore(id)) continue;
			res[(*this)(u, id)].push_back(u);
		}
		return res;
	}
	void set_ignoration_rule(const function<bool(int)> &f){
		ignore = f;
	}
	void reset_ignoration_rule(){
		ignore = nullptr;
	}
	friend ostream &operator<<(ostream &out, const graph &g){
		for(auto id = 0; id < (int)g.edge.size(); ++ id){
			if(g.ignore && g.ignore(id)) continue;
			auto &e = g.edge[id];
			out << "{" << e.from << ", " << e.to << ", " << e.cost << "}\n";
		}
		return out;
	}
};

// Requires graph
template<class T>
struct dfs_forest{
	int n;
	T base_dist;
	vector<T> dist;
	vector<int> pv;
	vector<int> pe;
	vector<int> order;
	vector<int> pos;
	vector<int> end;
	vector<int> size;
	vector<int> root_of;
	vector<int> root;
	vector<int> depth;
	vector<int> min_depth;
	vector<int> min_depth_origin;
	vector<int> min_depth_spanning_edge;
	// extra_edge[u]: adjacent edges of u which is not part of the spanning forest found during the last dfs-like run.
	vector<vector<int>> extra_edge;
	vector<int> was;
	dfs_forest(T base_dist = 0): base_dist(base_dist){ }
	void init(int n){
		this->n = n;
		pv.assign(n, -1);
		pe.assign(n, -1);
		order.clear();
		pos.assign(n, -1);
		end.assign(n, -1);
		size.assign(n, 0);
		root_of.assign(n, -1);
		root.clear();
		depth.assign(n, -1);
		min_depth.assign(n, -1);
		min_depth_origin.assign(n, -1);
		min_depth_spanning_edge.assign(n, -1);
		dist.assign(n, base_dist);
		extra_edge.assign(n, {});
		was.assign(n, -2);
		attempt = -1;
	}
	int attempt;
	// O(# of nodes reachable from u)
	template<class U, class F = plus<>>
	void _dfs(const graph<U> &g, int u, F UT = plus<>()){
		depth[u] = 0;
		dist[u] = base_dist;
		root_of[u] = u;
		root.push_back(u);
		pv[u] = pe[u] = -1;
		auto recurse = [&](auto self, int u)->void{
			was[u] = attempt;
			pos[u] = (int)order.size();
			order.push_back(u);
			size[u] = 1;
			min_depth[u] = depth[u];
			min_depth_origin[u] = u;
			min_depth_spanning_edge[u] = -1;
			for(auto id: g.adj[u]){
				if(id == pe[u] || g.ignore && g.ignore(id)) continue;
				int v = g(u, id);
				if(was[v] == attempt){
					if(min_depth[u] > depth[v]){
						min_depth[u] = depth[v];
						min_depth_spanning_edge[u] = id;
					}
					if(pe[u] != id) extra_edge[u].push_back(id);
					continue;
				}
				depth[v] = depth[u] + 1;
				dist[v] = UT(g.edge[id].cost, dist[u]);
				pv[v] = u;
				pe[v] = id;
				root_of[v] = root_of[u];
				self(self, v);
				size[u] += size[v];
				if(min_depth[u] > min_depth[v]){
					min_depth[u] = min_depth[v];
					min_depth_origin[u] = min_depth_origin[v];
					min_depth_spanning_edge[u] = min_depth_spanning_edge[v];
				}
			}
			end[u] = (int)order.size();
		};
		recurse(recurse, u);
	}
	// O(# of nodes reachable from src)
	template<class U, class F = plus<>>
	void dfs(const graph<U> &g, const vector<int> &src, F UT = plus<>()){
		assert(g.n <= n);
		root.clear(), order.clear();
		++ attempt;
		for(auto u: src){
			assert(0 <= u && u < g.n);
			if(was[u] != attempt) _dfs(g, u, UT);
		}
	}
	// O(n + m)
	template<class U, class F = plus<>>
	void dfs_all(const graph<U> &g, F UT = plus<>()){
		assert(g.n <= n);
		root.clear(), order.clear();
		++ attempt;
		for(auto u = 0; u < g.n; ++ u) if(was[u] != attempt) _dfs(g, u, UT);
	}
	// Check if u is visited during the last dfs-like call.
	bool visited(int u) const{
		assert(0 <= u && u < n);
		return was[u] == attempt;
	}
	// Check if u is an ancestor of v in some spanning tree.
	bool ancestor_of(int u, int v) const{
		assert(visited(u) && visited(v));
		return pos[u] <= pos[v] && end[v] <= end[u];
	}
	// Check if any cycle is found during the last dfs-like call.
	// If must_contain_root = true, the sought cycle is forced to contain one of the root of the trees.
	template<class U>
	optional<pair<int, vector<int>>> find_any_cycle(const graph<U> &g, bool must_contain_root = false) const{
		for(auto u: order) for(auto id: extra_edge[u]){
			int v = g(u, id);
			if(!ancestor_of(v, u) || must_contain_root && root_of[v] != v) continue;
			vector<int> cycle_edge;
			while(u != v) cycle_edge.push_back(pe[u]), u = pv[u];
			reverse(cycle_edge.begin(), cycle_edge.end());
			cycle_edge.push_back(id);
			return pair{v, cycle_edge};
		}
		return {};
	}
};

int main(){
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(ios::badbit | ios::failbit);
	int n;
	cin >> n;
	graph<int> g(n);
	for(auto i = 0; i < n - 1; ++ i){
		int u, v;
		cin >> u >> v, -- u, -- v;
		g.link(u, v, 1);
	}
	dfs_forest<int> df;
	df.init(n);
	df.dfs(g, {0});
	vector<array<int, 4>> cnt(n);
	long long res = 0;
	for(auto u: df.order | ranges::views::reverse){
		++ cnt[u][0];
		for(auto id: g.adj[u]){
			if(id == df.pe[u]){
				continue;
			}
			int v = g(u, id);
			for(auto d = 1; d <= 2; ++ d){
				for(auto e = 0; e <= 2 - d; ++ e){
					res += 1LL * cnt[u][d] * cnt[v][e];
				}
			}
			for(auto d = 0; d <= 2; ++ d){
				cnt[u][d + 1] += cnt[v][d];
			}
		}
		for(auto d = 1; d <= 3; ++ d){
			res += cnt[u][d];
		}
	}
	cout << res << "\n";
	return 0;
}

/*

*/
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