Submission #435016

#	Time	Username	Problem	Language	Result	Execution time	Memory
435016		grt	Keys (IOI21_keys)	C++17	67 / 100	2603 ms	203368 KiB

keys

#include <bits/stdc++.h>
#define ST first
#define ND second
#define PB push_back

using namespace std;
using ll = long long;
using pi = pair<int,int>;
using vi = vector<int>;

const int nax = 300 * 1000 + 10, INF = 1e9;
int n, m, nr;
map<int, vi>V[nax];
bool vis[2 * nax];
vi seen;
vi G[2 * nax];
vi Grev[2 * nax];
int topo[2 * nax];
int SCC[2 * nax];
bool ok[2 * nax];
int color;
int cc[nax];
int cnt[2 * nax], rep[2 * nax];
bool visited[nax];
bool done[nax];
vi verToAC[nax];
vector<pi>V2[nax];

void dfs(int x, int col) {
	vis[x] = true;
	seen.PB(x);
	for(auto ed : V[col][x]) if(!vis[ed]) {
		dfs(ed, col);
	}
}

void dfs2(int x) {
	vis[x] = true;
	for(int nbh : G[x]) {
		if(!vis[nbh]) {
			dfs2(nbh);
		}
	}
	topo[nr++] = x;
}

void dfs3(int x) {
	vis[x] = true;
	SCC[x] = color;
	if(x < n) rep[color] = x;
	if(x < n) cnt[color]++;
	for(int nbh : Grev[x]) if(!vis[nbh]) {
		dfs3(nbh);
	}
}

queue<int>Q;
vi saw, sawC;

void dfss(int x) {
	visited[x] = true;
	saw.PB(x);
	//cout << "VER: " << x << "\n";
	Q.push(cc[x]);
	for(auto nbh : V2[x]) if(!visited[nbh.ST]) {
		if(done[nbh.ND]) {
			dfss(nbh.ST);
		} else {
			verToAC[nbh.ND].PB(nbh.ST);
			sawC.PB(nbh.ND);
		}
	}
}

vi alg(int x) {
	saw = {};
	sawC = {};
	//for(int i = 0; i < n; ++i) {
		//done[i] = visited[i] = false;
	//}
	visited[x] = true;
	Q.push(cc[x]);
	saw.PB(x);
	for(auto nbh : V2[x]) {
		verToAC[nbh.ND].PB(nbh.ST);
		sawC.PB(nbh.ND);
	}
	vi rem = {};
	while(!Q.empty()) {
		x = Q.front();
		Q.pop();
		//cout << "COL: " << x << "\n";
		if(done[x]) continue;
		rem.PB(x);
		done[x] = true;
		for(auto y : verToAC[x]) {
			if(!visited[y]) dfss(y);
		}
	}
	for(int xx : rem) {
		done[xx] = false;
	}
	for(int xx : saw) {
		visited[xx] = false;
	}
	for(int xx : sawC) {
		verToAC[xx].clear();
	}
	return saw;
}

vi find_reachable(vi r, vi u, vi v, vi c) {
	n = (int)r.size();
	m = (int)u.size();
	for(int i = 0; i < m; ++i) {
		V[c[i]][u[i]].PB(v[i]);
		V[c[i]][v[i]].PB(u[i]);
		V2[u[i]].emplace_back(v[i], c[i]);
		V2[v[i]].emplace_back(u[i], c[i]);
		
	}
	for(int i = 0; i < n; ++i) {
		cc[i] = r[i];
	}
	int ver = n-1;
	for(int i = 0; i < n; ++i) {
		for(auto it : V[i]) {
			if(!vis[it.ST]) {
				seen.clear();
				dfs(it.ST, i);
				bool any = false;
				for(auto x : seen) {
					if(r[x] == i) any = true;
				}
				if(!any) continue;
				ver++;
				for(auto x : seen) {
					G[ver].PB(x);
					Grev[x].PB(ver);
					if(r[x] == i) {
						G[x].PB(ver);
						Grev[ver].PB(x);
					}
				}
			}
		}
		for(auto it : V[i]) vis[it.ST] = false;
	}
	for(int i = 0; i <= ver; ++i) {
		if(!vis[i]) {
			dfs2(i);
		}
	}
	for(int i = 0; i <= ver; ++i) {
		vis[i] = false;
	}
	for(int i = ver; i >= 0; --i) {
		if(!vis[topo[i]]) {
			color++;
			dfs3(topo[i]);
		}
	}
	for(int i = 0; i <= ver; ++i) ok[i] = false;
	for(int i = 0; i < n; ++i) ok[SCC[i]] = true;
	for(int i = 0; i <= ver; ++i) {
		for(int nbh : G[i]) {
			if(SCC[nbh] != SCC[i]) {
				ok[SCC[i]] = false;
			}
		}
	}
	vector<vi>com;
	int mi = INF;
	for(int i = 1; i <= color; ++i) {
		if(!ok[i]) continue;
		com.PB(alg(rep[i]));
		//cout << rep[i] << "\n";
		//for(int x : com.back()) {
			//cout << x << " ";
		//}
		//cout << "\n";
		mi = min(mi, (int)com.back().size());
	}
	//cout << "\n";
	vector<int>ans(n);
	for(int i = 0; i < n; ++i) ans[i] = false;
	for(auto vc : com) {
		if((int)vc.size() == mi) {
			for(int x : vc) {
				ans[x] = true;
			}
		}
	}
	//for(int i = 0; i < n; ++i) {
		//if(ok[SCC[i]] && cnt[SCC[i]] == mi) {
			//ans[i] = true;
		//} else {
			//ans[i] = false;
		//}
	//}
	return ans;
}

//int main() {
	//ios_base::sync_with_stdio(0);
	//cin.tie(0);
	//int N, M;
	//cin >> N >> M;
	//vi r(N), u(M), v(M), c(M);
	//for(int i = 0; i < N; ++i) {
		//cin >> r[i];
	//}
	//for(int i = 0; i < M; ++i) {
		//cin >> u[i] >> v[i] >> c[i];
	//}
	//vi w = find_reachable(r,u,v,c);
	//vi w = find_reachable({0, 1, 1, 2},{0, 0, 1, 1, 3}, {1, 2, 2, 3, 1}, {0, 0, 1, 0, 2});
	//vi w = find_reachable({0, 1, 1, 2, 2, 1, 2},{0, 0, 1, 1, 2, 3, 3, 4, 4, 5},
//{1, 2, 2, 3, 3, 4, 5, 5, 6, 6},
//{0, 0, 1, 0, 0, 1, 2, 0, 2, 1});
	//vi w = find_reachable({0, 0, 0}, {0}, {1}, {0});
	//for(int x : w) {
		//cout << x << " ";
	//}
//}

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 30 / 30
• Subtask 5: 0 / 33