Submission #500564

#	Time	Username	Problem	Language	Result	Execution time	Memory
500564		sidon	Parachute rings (IOI12_rings)	C++17	100 / 100	481 ms	48348 KiB

rings

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

array<int, 2> g[1<<20];
int N, p, j;

struct Solver {
	int e[1<<20], d[1<<20] = {};
	int maxDeg = 0, cycle = -1, rem = -1;
	void add(int u, int v) {
		if(u == rem || v == rem || maxDeg > 2) return;
		maxDeg = max({maxDeg, ++d[u], ++d[v]});

		while(e[u] >= 0) u = e[u];
		while(e[v] >= 0) v = e[v];
		
		if(u == v) {
			cycle = cycle >= 0 ? N : 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) {
	if(!p) {
		s[0].add(A, B);
		g[j++] = {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(int k = 0; k < j; k++)
				for(int i : {0, 1})
					if(g[k][i] == s[1].rem) s[++p].rem = g[k][!i];
			for(int i = 1; i < 5; i++)
				for(int k = 0; k < j; k++)
					s[i].add(g[k][0], g[k][1]);
		}
	} else
		for(int i = 1; i < 5; i++)
			s[i].add(A, B);
}
int CountCritical() {
	int res = 0;
	if(p)
		for(int i = 1; i < 5; i++)
			res += s[i].get() > 0;
	else res = abs(s[0].get());
	return res;
}

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