제출 #408112

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
408112		Kevin_Zhang_TW	Simurgh (IOI17_simurgh)	C++17	0 / 100	421 ms	12028 KiB

simurgh

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

const int MAX_N = 505, MAX_M = MAX_N * MAX_N;

#include "simurgh.h"

int qry(const vector<int> &r) { return count_common_roads(r); }

struct dsu {
	vector<int> g, sz;
	dsu (int n) { g.resize(n+10), sz.resize(n+10, 1), iota(AI(g), 0); }
	int F(int i) { return i == g[i] ? i : g[i] = F(g[i]); }
	int S(int i) { return sz[ F(i) ]; }
	bool M(int a, int b) { 
		a = F(a), b = F(b);
		if (a == b) return false;
		if (sz[a] < sz[b]) swap(a, b);
		return sz[a] += sz[b], g[b] = a, true;
	}
};

int id[MAX_N][MAX_N], m, n;
bool isin[MAX_N][MAX_N], is1[MAX_N][MAX_N];

struct tree {
	vector<pair<int,int>> alle;
	vector<int> get_cycle(int a, int b) {
		vector<vector<int>> edge(n);
		for (auto [a, b] : alle)
			edge[a].pb(b), edge[b].pb(a);

		vector<int> res, stk;

		function<bool(int,int)> dfs = [&](int x, int lst) {
			stk.pb(x);
			if (x == b) {
				res = stk;
				return true;
			}
			for (int u : edge[x]) if (u != lst) {
				if (dfs(u, x)) return true;
			}
			stk.pop_back();
			return false;
		};

		dfs(a, a);

		return res;
	}
	void remove(int a, int b) {
		if (a > b) swap(a, b);
		alle.erase(find(AI(alle), make_pair(a, b)));
	}
	void add_edge(int a, int b) { if (a > b) swap(a, b); alle.pb(a, b); }
};

vector<int> operator - (vector<int> a, int b) { a.erase(find(AI(a), b)); return a; }
vector<int> to_id(vector<pair<int,int>> a) { vector<int> b; for (auto [x, y] : a) b.pb(id[x][y]); return b; }
vector<int> operator + (vector<int> a, int b) { a.pb(b); return a; }

std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v) {
	::n = n;
	m = u.size();
	vector<pair<int,int>> alle(m);
	for (int i = 0;i < m;++i) {
		id[v[i]][u[i]] = id[u[i]][v[i]] = i;
		alle[i] = {u[i], v[i]};
	}

	// I need to find a tree
	vector<pair<int,int>> out, bad;
	tree T;
	{
		dsu D(n);
		for (auto [a, b] : alle) {
			if (D.M(a, b))
				T.add_edge(a, b);
			else
				out.pb(a, b);
		}
	}

	dsu allz(n);
	auto upd = [&](int a, int b) {
		if (allz.M(a, b)) {
			bad.pb(a, b);
			isin[a][b] = isin[b][a] = true;
		}
	};

	// then I want to find a forest which has all 0
	for (auto [a, b] : out) {
		if (allz.F(a) == allz.F(b)) continue;

		auto cir = T.get_cycle(a, b);
		vector<int> tall;
		for (auto [x, y] : T.alle)
			tall.pb(id[x][y]);

		int old = qry(tall);

		for (int i = 1;i < cir.size();++i) {
			int x = cir[i-1], y = cir[i];

			int val = qry(tall - id[x][y] + id[a][b]);

			if (val < old) 
				break;
			if (val > old) {
				T.remove(x, y);
				T.add_edge(a, b);
				a = x, b = y;
				break;
			}
		}

		upd(a, b);
	}

	// then I need to put the bridges back to both ANS, and BAD

	dsu G(n);
	vector<int> ans;

	// cnt_bridges

	int cnt_b = n-1 - bad.size();

	for (auto [a, b] : T.alle)
		if (allz.M(a, b)) {
			bad.pb(a, b);
			ans.pb(id[a][b]);
			isin[a][b] = isin[b][a] = true;
			G.M(a, b);
			is1[b][a] = is1[a][b] = true;
		}

	DE(cnt_b, qry(to_id(bad)), ans.size());


	while (alle.size()) {
		DE(alle.size());
		dsu D(n);
		vector<pair<int,int>> now;
		int sz = 0;
		for (auto [a, b] : alle) {
			if (!isin[a][b] && G.F(a) != G.F(b)) {
				if (D.M(a, b))
					now.pb(a, b);
				else alle[sz++] = {a, b};
			}
		}
		alle.resize(sz);
		int osz = now.size(), cnt_b = 0;
		DE(osz);
		
		for (auto [a, b] : bad)
			if (D.M(a, b)) {
				now.pb(a, b);
				cnt_b += is1[a][b];
			}

		int val = qry(to_id(now));
		if (val == cnt_b) continue;
		for (int i = cnt_b + 1;i <= val;++i) {
			int l = 0, r = n-cnt_b, m;
			while (l < r) {
				m = l + r >> 1;
				vector<pair<int,int>> q;
				dsu D(n);
				for (int j = 0;j <= m;++j) {
					D.M(now[j].first, now[j].second);
					q.pb(now[j]);
				}
				for (auto [a, b] : bad)
					if (D.M(a, b))
						q.pb(a, b);

				if (qry(to_id(q)) >= i)
					r = m;
				else
					l = m+1;
			}
			auto [a, b] = now[l];
			ans.pb(id[a][b]);
		DE(a, b);
			G.M(a, b);
		}
	}
	return ans;
}

컴파일 시 표준 에러 (stderr) 메시지

simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:118:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |   for (int i = 1;i < cir.size();++i) {
      |                  ~~^~~~~~~~~~~~
simurgh.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
simurgh.cpp:154:2: note: in expansion of macro 'DE'
  154 |  DE(cnt_b, qry(to_id(bad)), ans.size());
      |  ^~
simurgh.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
simurgh.cpp:158:3: note: in expansion of macro 'DE'
  158 |   DE(alle.size());
      |   ^~
simurgh.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
simurgh.cpp:171:3: note: in expansion of macro 'DE'
  171 |   DE(osz);
      |   ^~
simurgh.cpp:184:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  184 |     m = l + r >> 1;
      |         ~~^~~
simurgh.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
simurgh.cpp:202:3: note: in expansion of macro 'DE'
  202 |   DE(a, b);
      |   ^~
simurgh.cpp:170:7: warning: unused variable 'osz' [-Wunused-variable]
  170 |   int osz = now.size(), cnt_b = 0;
      |       ^~~
simurgh.cpp:143:6: warning: unused variable 'cnt_b' [-Wunused-variable]
  143 |  int cnt_b = n-1 - bad.size();
      |      ^~~~~

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• Subtask 2: 0 / 17
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30