Submission #201749

#	Time	Username	Problem	Language	Result	Execution time	Memory
201749		alishahali1382	Matching (COCI20_matching)	C++14	5 / 110	22 ms	15356 KiB

matching

#include <bits/stdc++.h>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;

const ld eps=1e-7;
const int inf=1000000010;
const ll INF=10000000000000010LL;
const int mod = 1000000007;
const int MAXN = 100010, SQ=320, CNT=MAXN/SQ+1;

inline void erase(vector<int> &vec, int x){
	if (vec.back()!=x) swap(vec[0], vec[1]);
	vec.pop_back();
}

int n, m, k, u, v, x, y, t, a, b;
int X[MAXN], Y[MAXN];
bool mark[MAXN];
vector<int> G[MAXN], vx[MAXN], vy[MAXN];
vector<pii> ans;
queue<int> Q;

inline bool bad(int a, int b, int c, int d){
	bool t1=(X[a]==X[b]), t2=(X[c]==X[d]);
	if (t1==t2) return 0;
	if (t1){
		swap(a, c);
		swap(b, d);
	}
	if (X[c]<X[a] || X[b]<X[c]) return 0;
	if (Y[c]>Y[d]) swap(c, d);
	return (Y[c]<=Y[a] && Y[a]<=Y[d]);
}

inline void disjoint(int u, int v){
	erase(G[u], v);
	erase(G[v], u);
}

struct SQRT{
	vector<int> vec[MAXN];
	int L[MAXN], R[MAXN];
	pii block[CNT][SQ];   //  {L, pos}
	pii mx[CNT][SQ];      //  {R, pos}
	
	void rebuild(int id){
		for (int i=0; i<SQ; i++) block[id][i]={L[SQ*id+i], SQ*id+i};
		sort(block[id], block[id]+SQ);
		for (int i=0; i<SQ; i++) mx[id][i]={R[block[id][i].second], block[id][i].second};
		for (int i=1; i<SQ; i++) mx[id][i]=max(mx[id][i], mx[id][i-1]);
	}
	
	void Draw(int l, int r, int h){
		if (l>r) swap(l, r);
		int idl=l/SQ, idr=r/SQ;
		while (l<r){
			//debug(l)
			//debug2(L[l], R[l])
			if (l%SQ==0 && l+SQ<=r){
				int id=l/SQ;
				while (1){
					int tmp=lower_bound(block[id], block[id]+SQ, pii(h, 0))-block[id]-1;
					if (tmp==-1 || mx[id][tmp].first<h) break ;
					int pos=mx[id][tmp].second;
					disjoint(vec[pos][0], vec[pos][1]);
					L[pos]=R[pos]=0;
					rebuild(id);
				}
				l+=SQ;
			}
			else{
				if (L[l]<h && h<R[l]) disjoint(vec[l][0], vec[l][1]);
				l++;
			}
		}
		rebuild(idl);
		rebuild(idr);
	}
	
} SQX, SQY;

int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>n;
	for (int i=1; i<=n; i++){
		cin>>X[i]>>Y[i];
		if (vx[X[i]].size()){
			int j=vx[X[i]][0];
			if (Y[i]==Y[j]){
				mark[i]=mark[j]=1;
				ans.pb({j, i});
				continue ;
			}
			G[i].pb(j);
			G[j].pb(i);
		}
		if (vy[Y[i]].size()){
			int j=vy[Y[i]][0];
			G[i].pb(j);
			G[j].pb(i);
		}
		vx[X[i]].pb(i);
		vy[Y[i]].pb(i);
	}
	
	for (int i=0; i<MAXN; i++){
		if (vx[i].size()==2 && Y[vx[i][0]]>Y[vx[i][1]]) swap(vx[i][0], vx[i][1]);
		if (vy[i].size()==2 && X[vy[i][0]]>X[vy[i][1]]) swap(vy[i][0], vy[i][1]);
		SQX.vec[i]=vx[i];
		SQY.vec[i]=vy[i];
	}
	
	//debugv(vx[2])
	
	for (int i=0; i<MAXN; i++) if (vx[i].size()==2) SQX.L[i]=Y[vx[i][0]], SQX.R[i]=Y[vx[i][1]];
	for (int i=0; i<MAXN; i++) if (vy[i].size()==2) SQY.L[i]=X[vy[i][0]], SQY.R[i]=X[vy[i][1]];
	for (int i=0; i<CNT; i++) SQX.rebuild(i), SQY.rebuild(i);
	
	/*
	SQX.Draw(1, 3, 2);
	debugv(G[3])
	
	return 0;
	*/
	
	for (int i=1; i<=n; i++) if (G[i].size()<2) Q.push(i);
	while (Q.size()){
		int v=Q.front();
		Q.pop();
		if (mark[v]) continue ;
		if (G[v].size()==0) kill("NE")
		int u=G[v][0];
		mark[v]=mark[u]=1;
		ans.pb({u, v});
		//debug2(u, v)
		for (int i:G[u]) if (i!=v){
			erase(G[i], u);
			Q.push(i);
		}
		
		if (Y[u]==Y[v]) SQX.Draw(X[u], X[v], Y[u]);
		else SQY.Draw(Y[u], Y[v], X[u]);
		
	}
	
	
	
	for (int i=1; i<=n; i++) if (!mark[i]){
		int j=G[i][0];
		if (X[i]!=X[j]) j=G[i][1];
		ans.pb({i, j});
		mark[i]=mark[j]=1;
	}
	
	cout<<"DA\n";
	for (pii p:ans) cout<<p.first<<' '<<p.second<<'\n';
	
	return 0;
}
/*
4
10 20
30 20
20 30
20 10

*/

• Subtask 1: 5 / 5
• Subtask 2: 0 / 6
• Subtask 3: 0 / 7
• Subtask 4: 0 / 40
• Subtask 5: 0 / 52