Submission #393592

#	Time	Username	Problem	Language	Result	Execution time	Memory
393592		JimmyZJX	Simurgh (IOI17_simurgh)	C++14	51 / 100	295 ms	4784 KiB

simurgh

#include <iostream>
#include <fstream>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cassert>
#include <tuple>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <numeric>

using namespace std;

typedef long long LL;
typedef vector<int> Vi;
typedef vector<LL> VL;
typedef vector<bool> Vb;
typedef vector<vector<int>> Vii;
typedef vector<vector<vector<int>>> Viii;
typedef vector<vector<pair<int, int>>> Vip;

#define forR(i, n) for (int i = 0; i < (n); i++)

int count_common_roads(const Vi& r);

Vip nbs; // {nb, edge}
Viii nbgps; // index
int N;
Vi pathProp; // 0: unknown; 1: royale; 2: not royale
Vb pathPending;

Vi parent; // disjoint set

int getRoot(int x) {
	if (x == parent[x]) return x;
	int ppx = getRoot(parent[x]);
	parent[x] = ppx;
	return ppx;
}
void setEq(int x, int y) {
	int px = getRoot(x), py = getRoot(y);
	parent[py] = px;
	if (pathProp[py] > 0) {
		assert(pathProp[px] == 0 || pathProp[px] == pathProp[py]);
		pathProp[px] = pathProp[py];
	}
	pathPending[px] = pathPending[py] = true;
}
void set_prop(int e, int prop) {
	int re = getRoot(e);
	assert(pathProp[re] == 0 || pathProp[re] == prop);
	pathProp[re] = prop;
}
int get_prop(int e) {
	int re = getRoot(e);
	assert(pathProp[re] > 0);
	return pathProp[re];
}
bool has_prop(int e) {
	int re = getRoot(e);
	return pathProp[re] > 0;
}

pair<Vi, Vb> gen_tree(int root, int node = -1) {
	Vb vis(N); vis[root] = true;
	queue<int> q;
	if (node < 0) {
		for (auto& gps : nbgps[root]) {
			int node = nbs[root][gps[0]].first;
			vis[node] = true;
			q.push(node);
		}
	} else {
		vis[node] = true;
		q.push(node);
	}

	Vi edges;
	while (!q.empty()) {
		int x = q.front(); q.pop();
		for (auto nb : nbs[x]) {
			if (!vis[nb.first]) {
				vis[nb.first] = true;
				q.push(nb.first);
				edges.push_back(nb.second);
			}
		}
	}

	if (node < 0) {
		assert(edges.size() == N - 1 - nbgps[root].size());
	}
	return { edges, vis };
}

Vi find_roads(int n, Vi u, Vi v) {
	nbs = Vip(n);
	nbgps = Viii(n);
	N = n;
	int m = u.size();
	pathProp = Vi(m);
	pathPending = Vb(m);

	parent = Vi();
	forR(i, m) parent.push_back(i);

	forR(i, m) {
		nbs[u[i]].push_back({ v[i], i });
		nbs[v[i]].push_back({ u[i], i });
	}

	forR(i, n) {
		Vb visited(n);
		forR(j, nbs[i].size()) {
			int node = nbs[i][j].first;
			if (visited[node]) continue;
			auto pair = gen_tree(i, node);
			Vb& vis = pair.second;

			nbgps[i].push_back(Vi());
			forR(k, nbs[i].size()) {
				int nk = nbs[i][k].first;
				if (vis[nk]) {
					nbgps[i].back().push_back(k);
					visited[nk] = true;
				}
			}
		}
	}

	forR(i, n) {
		Vi sTree = gen_tree(i).first;

		Vi sTree0 = sTree; // all first edges
		forR(k, nbgps[i].size()) {
			int edge = nbs[i][nbgps[i][k][0]].second;
			sTree0.push_back(edge);
		}
		int val0 = count_common_roads(sTree0);

		forR(igp, nbgps[i].size()) {
			auto& gp = nbgps[i][igp];
			if (gp.size() == 1) {
				set_prop(nbs[i][gp[0]].second, 1);
				continue;
			}

			Vi gpTree = sTree;
			forR(k, nbgps[i].size()) { // edges of other groups
				if (k == igp) continue;
				int edge = nbs[i][nbgps[i][k][0]].second;
				gpTree.push_back(edge);
			}

			int edge0 = nbs[i][gp[0]].second;
			bool someHasProp = has_prop(edge0);

			for (int j = 1; j < gp.size(); j++) {
				int edge = nbs[i][gp[j]].second;
				if (has_prop(edge)) {
					if (!someHasProp) someHasProp = true;
					else continue;
				}
				gpTree.push_back(edge);
				int valJ = count_common_roads(gpTree);
				gpTree.pop_back();

				if (val0 == valJ) {
					setEq(edge0, edge);
				} else if (val0 < valJ) { // j royale
					set_prop(edge0, 2);
					set_prop(edge, 1);
				} else { // 0 royale
					set_prop(edge0, 1);
					set_prop(edge, 2);
				}
			}
			if (!has_prop(edge0)) {
				// pending edge0: all pending => all set to 1
				set_prop(edge0, 1);
			}
		}
	}

	Vi royaleEdges;
	forR(i, m) if (get_prop(i) == 1) royaleEdges.push_back(i);

	assert(royaleEdges.size() == n - 1);
	return royaleEdges;
}


#ifdef TEST_LOCAL
set<int> _ry{ 5,1,0 };
int count_common_roads(const Vi& r) {
	int cnt = 0;
	for (int e : r)
		if (_ry.count(e) > 0)
			cnt++;
	return cnt;
}

int main() {
	auto r = find_roads(4, Vi{ 0, 0, 0, 1, 1, 2 }, Vi{ 1, 2, 3, 3, 2, 3 }); //

	return 0;
}
#endif

Compilation message (stderr)

simurgh.cpp: In function 'Vi find_roads(int, Vi, Vi)':
simurgh.cpp:28:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 | #define forR(i, n) for (int i = 0; i < (n); i++)
      |                                      ^
simurgh.cpp:120:3: note: in expansion of macro 'forR'
  120 |   forR(j, nbs[i].size()) {
      |   ^~~~
simurgh.cpp:28:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 | #define forR(i, n) for (int i = 0; i < (n); i++)
      |                                      ^
simurgh.cpp:127:4: note: in expansion of macro 'forR'
  127 |    forR(k, nbs[i].size()) {
      |    ^~~~
simurgh.cpp:28:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 | #define forR(i, n) for (int i = 0; i < (n); i++)
      |                                      ^
simurgh.cpp:141:3: note: in expansion of macro 'forR'
  141 |   forR(k, nbgps[i].size()) {
      |   ^~~~
simurgh.cpp:28:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 | #define forR(i, n) for (int i = 0; i < (n); i++)
      |                                      ^
simurgh.cpp:147:3: note: in expansion of macro 'forR'
  147 |   forR(igp, nbgps[i].size()) {
      |   ^~~~
simurgh.cpp:28:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 | #define forR(i, n) for (int i = 0; i < (n); i++)
      |                                      ^
simurgh.cpp:155:4: note: in expansion of macro 'forR'
  155 |    forR(k, nbgps[i].size()) { // edges of other groups
      |    ^~~~
simurgh.cpp:164:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  164 |    for (int j = 1; j < gp.size(); j++) {
      |                    ~~^~~~~~~~~~~
In file included from /usr/include/c++/9/cassert:44,
                 from simurgh.cpp:6:
simurgh.cpp:194:28: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  194 |  assert(royaleEdges.size() == n - 1);
      |         ~~~~~~~~~~~~~~~~~~~^~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 17 / 17
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30