Submission #500514

#	Time	Username	Problem	Language	Result	Execution time	Memory
500514		sidon	Parachute rings (IOI12_rings)	C++17	38 / 100	4056 ms	61820 KiB

rings

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

vector<array<int, 2>> g;
int N, p;

struct Solver {
	int e[1<<20], d[1<<20] = {};
	int maxDeg = 0, cycle = -1, rem = -1;
	int find(int u){
		return e[u] < 0 ? u : e[u] = find(e[u]);
	}
	void add(int u, int v) {
		
		if(u == rem || v == rem) return;
		maxDeg = max({maxDeg, ++d[u], ++d[v]});
		
		if((u = find(u)) == (v = find(v))) {
			cycle >= 0 ? maxDeg = 3 : cycle = u;
		} else {
			if(e[u] > e[v]) swap(u, v);
			e[u] += e[v], e[v] = u;
		}
	}
	int get() {
		if(maxDeg > 2) return 0;
		return cycle >= 0 ? e[cycle] : N;
	}
} s[5];

void Init(int N_) {
	N = N_;
	s[0].get();
	for(int i = 0; i < 5; i++)
		fill(s[i].e, s[i].e+N, -1);
}

void Link(int A, int B) {
	g.push_back({A, B});
	if(!p) {
		s[0].add(A, B);
		if(s[0].maxDeg > 2) {
			for(int i = 0; i < N; i++)
				if(s[0].d[i] > 2) s[p=1].rem = i;
			for(auto &[u, v] : g) {
				if(u == s[1].rem) s[++p].rem = v;
				if(v == s[1].rem) s[++p].rem = u;
			}
			for(int i = 1; i < 5; i++)
				for(auto &[u, v] : g)
					s[i].add(u, v);
		}
	} else {
		for(int i = 1; i < 5; i++)
			s[i].add(A, B);
	}
}

int CountCritical() {
	int res = 0;
	if(!p) res = abs(s[0].get());
	else {
		for(int i = 1; i < 5; i++)
			res += s[i].get() > 0;
	}
	return res;
}

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