Submission #137914

#	Time	Username	Problem	Language	Result	Execution time	Memory
137914		Utaha	Parachute rings (IOI12_rings)	C++14	100 / 100	2397 ms	127180 KiB

rings

#include <bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pdd;
#define IOS ios_base::sync_with_stdio(0); cin.tie(0)
#define ALL(a) a.begin(),a.end()
#define SZ(a) ((int)a.size())
#define F first
#define S second
#define REP(i,n) for(int i=0;i<((int)n);i++)
#define pb emplace_back
#define MP(a,b) make_pair(a,b)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
#define EL cout<<'\n'
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
	out<<'('<<P.F<<','<<P.S<<')';
	return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
	REP(i,SZ(V)) out<<V[i]<<((i!=SZ(V)-1)?" ":"");
	return out;
}
#define version 20190726
//}}}
const ll maxn=1000005;
const ll maxlg=20;
const ll INF64=1e18;
const int INF=0x3f3f3f3f;
const ll MOD=ll(1e9+7);
const ld PI=acos(-1);
const ld eps=1e-9;
//const ll p=880301;
//const ll P=31;

ll mypow(ll a,ll b){
	ll res=1LL;
	while(b){
		if(b&1) res=res*a%MOD;
		a=a*a%MOD;
		b>>=1;
	}
	return res;
}

struct DSU{
	int dsu[maxn];
	int sz[maxn];
	DSU(){}
	void init(int n){
		REP(i,n) dsu[i]=i,sz[i]=1;
	}
	int find(int u){
		if(dsu[u]==u) return u;
		return dsu[u]=find(dsu[u]);
	}
	void mrg(int u,int v){
		u=find(u);
		v=find(v);
		if(u==v) return;
		if(sz[u]<sz[v]) swap(u,v);
		dsu[v]=u;
		sz[u]+=sz[v];
	}
};
struct checker{
	int dsu[maxn];
	int sz[maxn];
	int deg[maxn];
	bool valid=1;
	checker(){}
	void init(int n){
		REP(i,n) dsu[i]=i,sz[i]=1;
	}
	int find(int u){
		if(dsu[u]==u) return u;
		return dsu[u]=find(dsu[u]);
	}
	void mrg(int u,int v){
		deg[u]++,deg[v]++;
		if(deg[u]==3||deg[v]==3) valid=0;
		u=find(u);
		v=find(v);
		if(u==v){
			valid=0;
			return;
		}
		if(sz[u]<sz[v]) swap(u,v);
		dsu[v]=u;
		sz[u]+=sz[v];
	}
};

int n;
bool stage=0;
int deg[maxn];
vector<int> edge[maxn];
vector<int> p;
DSU orig;
int ring=0;
int ringsz=-1;

checker nw[5];

void Init(int N){
	n=N;
	orig.init(N);
}

void Link(int A, int B) {
	deg[A]++;
	deg[B]++;
	edge[A].pb(B);
	edge[B].pb(A);
	bool f=0;
	if((!stage)&&(deg[A]==3)){
		f=1;
		stage=1;
		p.pb(A);
		for(int i:edge[A]) p.pb(i);

		REP(i,SZ(p)){
			nw[i].init(n);
			REP(j,n) for(int k:edge[j]){
				if(j<k&&j!=p[i]&&k!=p[i]){
					nw[i].mrg(j,k);
				}
			}
		}
	}
	if((!stage)&&(deg[B]==3)){
		f=1;
		stage=1;
		p.pb(B);
		for(int i:edge[B]) p.pb(i);

		REP(i,SZ(p)){
			nw[i].init(n);
			REP(j,n) for(int k:edge[j]){
				if(j<k&&j!=p[i]&&k!=p[i]){
					nw[i].mrg(j,k);
				}
			}
		}
	}
	if(stage==0){
		if(orig.find(A)==orig.find(B)){
			ring++;
			if(ring==1){
				ringsz=orig.sz[orig.find(A)];
			}
		}
		else{
			orig.mrg(A,B);
		}
	}
	else{
		if(f);
		else{
			REP(i,SZ(p)){
				if(p[i]!=A&&p[i]!=B){
					nw[i].mrg(A,B);
				}
			}
		}
	}
}

int CountCritical() {
	if(stage){
		int ans=0;
		REP(i,4) ans+=nw[i].valid;
		return ans;
	}
	else{
		if(ring>=2){
			return 0;
		}
		if(ring==1) return ringsz;
		return n;
	}
}

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