Submission #15785

#	Time	Username	Problem	Language	Result	Execution time	Memory
15785		myungwoo	Parachute rings (IOI12_rings)	C++14	100 / 100	2403 ms	52392 KiB

rings

#include <vector>
using namespace std;

#define MAXN 1000006
#define mp make_pair
#define pb push_back
#define sz(v) ((int)(v).size())
typedef pair<int,int> pii;

static int N,deg[MAXN],par[MAXN],size[MAXN];
static int _par[4][MAXN],_deg[4][MAXN],_target[4];
static int cycle_cnt,cycle_size;
static bool sw,_valid[4];
static vector<pii> edges;

int find(int n,int p[MAXN]=par){ return p[n]==n?n:(p[n]=find(p[n],p)); }

void Init(int n)
{
	int i;
	N = n;
	for (i=1;i<=N;i++) par[i] = i, size[i] = 1;
}

void addEdge(int a,int b)
{
	int i;
	for (i=0;i<4;i++){
		if (_target[i] == a || _target[i] == b) continue;
		if (++_deg[i][a] == 3) _valid[i] = 0;
		if (++_deg[i][b] == 3) _valid[i] = 0;
		int p = find(a,_par[i]), q = find(b,_par[i]);
		if (p == q) _valid[i] = 0;
		_par[i][q] = p;
	}
}

void reg(int n)
{
	int i,j,k=0;
	_target[k++] = n;
	for (i=0;i<sz(edges);i++){
		if (edges[i].first == n) _target[k++] = edges[i].second;
		if (edges[i].second == n) _target[k++] = edges[i].first;
	}
	for (i=0;i<4;i++){
		_valid[i] = 1;
		for (j=1;j<=N;j++) _par[i][j] = j;
	}
	for (i=0;i<sz(edges);i++) addEdge(edges[i].first,edges[i].second);
}

void Link(int a,int b)
{
	a++; b++;
	deg[a]++; deg[b]++;
	edges.pb(mp(a,b));
	if (!sw && deg[a] == 3) sw = 1, reg(a);
	else if (!sw && deg[b] == 3) sw = 1, reg(b);
	else if (!sw){
		a = find(a); b = find(b);
		if (a == b){
			cycle_cnt++;
			cycle_size = size[a];
		}else{
			par[b] = a;
			size[a] += size[b];
		}
	}else{
		addEdge(a,b);
	}
}

int CountCritical()
{
	if (cycle_cnt > 1) return 0;
	if (!sw){
		if (cycle_cnt) return cycle_size;
		return N;
	}
	int ret = 0,i;
	for (i=0;i<4;i++) ret += _valid[i];
	return ret;
}

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