Submission #229617

#	Time	Username	Problem	Language	Result	Execution time	Memory
229617		maruii	Parachute rings (IOI12_rings)	C++14	20 / 100	4096 ms	75368 KiB

rings

#include <bits/stdc++.h>
using namespace std;

int N, flag, cyc, up[1000005], par[1000005];
vector<int> edge[1000005], ans;


int fnd(int x) { return up[x] == x ? x : up[x] = fnd(up[x]); }
void Init(int N_) {
	N = N_;
	for (int i = 0; i < N; ++i) {
		up[i] = i;
		ans.push_back(i);
	}
}

void update(int x) {
	if (edge[x].size() < 3) return;
	vector<int> v;
	for (auto i : ans) {
		if (i == x) v.push_back(i);
		else if (edge[x].size() < 4) for (auto j : edge[x]) if (i == j) {
			v.push_back(i);
			break;
		}
	}
	ans = v;
}

void Link(int a, int b) {
	if (ans.empty()) return;
	edge[a].push_back(b);
	edge[b].push_back(a);
	update(a);
	update(b);
}

bool vi[1000005];
int dep[1000005];
void dfs(int x, int p) {
	vi[x] = 1;
	for (auto i : edge[x]) if (i != p) {
		if (vi[i]) {
			if (dep[i] < dep[x]) {
				vector<int> u, v;
				u.push_back(i);
				for (int j = fnd(x); j != fnd(i); j = fnd(par[j])) {
					up[j] = fnd(par[j]);
					u.push_back(j);
				}

				for (auto i : ans) {
					for (auto j : u) if (i == j) {
						v.push_back(i);
						break;
					}
				}
				ans = v;

			}
			continue;
		}
		par[i] = x;
		dep[i] = dep[x] + 1;
		dfs(i, x);
	}
}

int CountCritical() {
	for (int i = 0; i < N; ++i) vi[i] = 0;
	for (int i = 0; i < N; ++i) if (!vi[i]) {
		dep[i] = 0; 
		dfs(i, i);
	}
	return ans.size();
}

• Subtask 1: 20 / 20
• Subtask 2: 0 / 17
• Subtask 3: 0 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31