Submission #962036

#	Time	Username	Problem	Language	Result	Execution time	Memory
962036		pcc	Joker (BOI20_joker)	C++17	25 / 100	403 ms	33240 KiB

Joker

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

#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tlll tuple<ll,ll,ll>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,popcnt,sse4")

const int mxn = 4e5+30;
int N,M,Q;

struct DSU{
	vector<pii> sop,dop;
	vector<int> cop;
	bool cyc;
	int dsu[mxn],sz[mxn];
	void init(int n){
		cyc = false;
		for(int i = 0;i<=n;i++)dsu[i] = i,sz[i] = 1;
	}
	int root(int k){
		return k == dsu[k]?k:root(dsu[k]);
	}
	void onion(int a,int b){
		 a = root(a),b = root(b);
		 if(a == b){
			 sop.push_back(pii(0,0));
			 dop.push_back(pii(0,0));
			 return;
		 }
		 if(sz[a]<sz[b])swap(a,b);
		 sop.push_back(pii(a,sz[a]));
		 dop.push_back(pii(b,b));
		 dsu[b] = a;
		 sz[a] += sz[b];
		 return;
	}
	void roll(){
		for(int i = 0;i<2;i++){
		{
			auto [a,b] = sop.back();sop.pop_back();
			sz[a] = b;
		}{
			auto [a,b] = dop.back();dop.pop_back();
			dsu[a] = b;
		}{
			auto a = cop.back();cop.pop_back();
			cyc = a;
		}}
		return;
	}
	void add_edge(int a,int b){
		onion(a,b+N);
		onion(b,a+N);
		cop.push_back(cyc);
		if(root(a) == root(a+N))cyc = true;
		cop.push_back(cyc);
		if(root(b) == root(b+N))cyc = true;
		assert(cop.size() == dop.size());
		return;
	}
};

DSU dsu;
pii edges[mxn];
pii req[mxn];
int rp[mxn];

void dc(int l,int r,int sl,int sr){
	//cerr<<l<<' '<<r<<':'<<sl<<' '<<sr<<endl;
	if(l == r){
		for(int i = sl;i<=sr;i++){
			rp[i] = l;
		}
		return;
	}
	int mid = (l+r)>>1;
	bool f = false;
	for(int i = r;i>mid;i--){
		auto [a,b] = edges[i];
		dsu.add_edge(a,b);
	}
	//cerr<<l<<' '<<mid<<' '<<r<<":"<<sl<<' '<<sr<<','<<dsu.cyc<<endl;
	//for(int i = 1;i<=N;i++)cerr<<dsu.root(i)<<' ';cerr<<endl;
	if(dsu.cyc){
		for(int i = r;i>mid;i--){
			dsu.roll();
		}
		dc(mid+1,r,sl,sr);
		return;
	}
	int opt = sl;
	for(int i = sl;i<=sr;i++){
		auto [a,b] = edges[i];
		dsu.add_edge(a,b);
		opt = i;
		if(dsu.cyc)break;
	}
	for(int i = sl;i<=opt;i++){
		dsu.roll();
	}
	if(sl != opt)dc(l,mid,sl,opt-1);
	for(int i = r;i>mid;i--){
		dsu.roll();
	}
	for(int i = sl;i<opt;i++){
		auto [a,b] = edges[i];
		dsu.add_edge(a,b);
	}
	dc(mid+1,r,opt,sr);
	for(int i = sl;i<opt;i++){
		dsu.roll();
	}
	return;
}

int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>N>>M>>Q;
	for(int i = 1;i<=M;i++)cin>>edges[i].fs>>edges[i].sc;
	for(int i = 1;i<=Q;i++)cin>>req[i].fs>>req[i].sc;
	edges[M+2] = edges[0] = edges[M+1] = pii(N+1,N+2);
	N += 2;
	dsu.init(N*2+10);

	dc(0,M+1,0,M);
	//for(int i = 0;i<=M;i++)cerr<<rp[i]<<' ';cerr<<endl;
	for(int i = 1;i<=Q;i++){
		auto [s,e] = req[i];
		if(rp[s-1]>=e+1)cout<<"YES\n";
		else cout<<"NO\n";
	}
	return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'void dc(int, int, int, int)':
Joker.cpp:82:7: warning: unused variable 'f' [-Wunused-variable]
   82 |  bool f = false;
      |       ^

• Subtask 1: 0 / 6
• Subtask 2: 0 / 8
• Subtask 3: 25 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29