제출 #151041

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
151041		aayush9	갈라파고스 여행 (FXCUP4_island)	C++17	31 / 100	5082 ms	498232 KiB

island

#include "island.h"

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

const int MAX_M = 300000;
const int GAP = 500;

struct UnionFind {
	int n;
	vector<int> uf,si,c;
	UnionFind(int n=0):n(n),uf(n),si(n,1){
		for(int i=0;i<n;++i) 
			uf[i]=i;
	}
	int find(int x){return x==uf[x]?x:find(uf[x]);}
	bool join(int x, int y, bool keep_track = 1){
		if((x=find(x))==(y=find(y))) return false;
		if(si[x]<si[y]) swap(x,y);
		si[x]+=si[y];uf[y]=x;
		if(keep_track) c.push_back(y);
		return true;
	}
	void rollback(){
		while(c.size()){
			int x=c.back(); c.pop_back();
			si[uf[x]]-=si[x];uf[x]=x;;
		}
	}
} UF[603];

struct UnionFindPathCompression {
	int n;
	vector<int> uf;
	UnionFindPathCompression(int n=0):n(n),uf(n){
		for(int i=0;i<n;++i) uf[i]=i;
	}
	int find(int x){return uf[x] = x==uf[x]?x:find(uf[x]);}
	void join(int x, int y){
		if((x=find(x))==(y=find(y))) return;
		uf[y]=x;
	}
};

vector<pair<int,int>> edges;
vector<int> pos[100005];

int M, N;

map<int,int> memo[100005];

void Init(int K, vector<int> F, vector<int> S, vector<int> E){
	N = F.size();
	M = S.size();

	edges.resize(M);
	for(int i=0;i<N;++i) memo[i].clear();
	for(int i=0;i<K;++i) pos[i].clear();

	for(int i=0;i<M;++i) edges[M-i-1] = {S[i], E[i]};

	for(int i=0;i<(int)F.size();++i)
		pos[F[i]].push_back(i);

	UnionFind cur(N);

	for(int i=0;i<M;++i){
		if(i%GAP==0) UF[i/GAP] = cur;
		cur.join(edges[i].first, edges[i].second, 0);
	}


	vector<pair<int,int>> queries;
	for(int finch=0;finch<K;++finch) if(pos[finch].size() >= GAP)
		for(int i=finch+1;i<K;++i) queries.push_back({finch,i});
	
	int Q = queries.size();
	
	vector<int> lo(Q,0), hi(Q,M-1);

	for(int iter=19;iter--;){

		vector<vector<int>> mid(M);
		for(auto i=0;i<Q;++i)
			mid[(lo[i]+hi[i])/2].push_back(i);

		UnionFind dsu(N);
		for(int i=0;i<M;++i){
			dsu.join(edges[i].first, edges[i].second, 0);
			for(auto j:mid[i]){
				int A = queries[j].first, B = queries[j].second;
				
				for(auto i:pos[A]) dsu.join(pos[A][0], i, 1);
				for(auto i:pos[B]) dsu.join(pos[B][0], i, 1);

				if(dsu.find(pos[A][0]) == dsu.find(pos[B][0]))
					hi[j] = i;
				else
					lo[j] = i + 1;

				dsu.rollback();
			}
		}
	}

	for(int i=0;i<Q;++i){
		// cout << queries[i].first << ' ' << queries[i].second << ' ' << M - hi[i] << '\n';
		memo[queries[i].first][queries[i].second] = max(memo[queries[i].first][queries[i].second], M - hi[i]);
	}
}

int Separate(int A, int B){
	if(A>B) swap(A,B);
	if(memo[A].count(B)) return memo[A][B];

	int bucket = 0, ans = -1;

	int lo = 0, hi = (M-1)/GAP;
	while(lo<hi){
		int b = (lo + hi + 1)/2;

		for(auto i:pos[A]) UF[b].join(pos[A][0], i, 1);
		for(auto i:pos[B]) UF[b].join(pos[B][0], i, 1);

		if(UF[b].find(pos[A][0]) == UF[b].find(pos[B][0])){
			hi = b - 1;
		}
		else{
			lo = b;
		}
		UF[b].rollback();
	}

	bucket = lo;

	for(auto i:pos[A]) UF[bucket].join(pos[A][0], i, 1);
	for(auto i:pos[B]) UF[bucket].join(pos[B][0], i, 1);

	int start = bucket * GAP;

	for(int i=start;i<=start+GAP && i<M; ++i){
		UF[bucket].join(edges[i].first, edges[i].second, 1);
		if(UF[bucket].find(pos[A][0]) == UF[bucket].find(pos[B][0])){
			ans = M - i;
			break;
		}
	}
	UF[bucket].rollback();
	return memo[A][B] = ans;
}

• Subtask 1: 31 / 31
• Subtask 2: 0 / 39
• Subtask 3: 0 / 30