Submission #836616

#	Time	Username	Problem	Language	Result	Execution time	Memory
836616		Baytoro	Fountain Parks (IOI21_parks)	C++17	5 / 100	697 ms	57268 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
//#include "grader.cpp"
using namespace std;
#define pb push_back
#define all(x) x.begin(), x.end()
#define fr first
#define sc second
const int N=2e5+5;
vector<array<int,3>> g[N];
int p[N];
vector<int> sz(N,1);
int f(int x){
	if(p[x]==x) return x;
	return p[x]=f(p[x]);
}
bool add(int a, int b){
	a=f(a);
	b=f(b);
	if(a==b) return 0;
	if(rand()%2) swap(a,b);//<-может лагать
	p[a]=b;
	sz[b]+=sz[a];
	return 1;
}
void add_edge(int a, int b, int u, int v){
	g[a].pb({b,u,v});
	g[b].pb({a,u,v});
}
int construct_roads(vector<int> x, vector<int> y) {
	int n=x.size();
	map<pair<int,int>,int> X,Y;
	for(int i=0;i<n;i++){
		p[i]=i;
		X[{x[i],y[i]}]=i;
	}
	vector<int> u,v,a,b;
	for(int i=0;i<n;i++){
		if(X.count({x[i]-2,y[i]})){
			int j=X[{x[i]-2,y[i]}];
			if(add(i,j)){
				u.pb(i);v.pb(j);
				a.pb(-1);b.pb(-1);
				int A=u.size()-1;
				if(Y.count({x[i]-1,y[i]-1})){
					int B=Y[{x[i]-1,y[i]-1}];
					add_edge(A,B,x[i]-1,y[i]-1);
					Y.erase({x[i]-1,y[i]-1});
				}
				else{
					Y[{x[i]-1,y[i]-1}]=A;
				}
				if(Y.count({x[i]-1,y[i]+1})){
					int B=Y[{x[i]-1,y[i]+1}];
					add_edge(A,B,x[i]-1,y[i]+1);
					Y.erase({x[i]-1,y[i]+1});
				}
				else{
					Y[{x[i]-1,y[i]+1}]=A;
				}
			}
		}
		if(X.count({x[i],y[i]-2})){
			int j=X[{x[i],y[i]-2}];
			if(add(i,j)){
				u.pb(i);v.pb(j);
				a.pb(-1);b.pb(-1);
				int A=u.size()-1;
				if(Y.count({x[i]-1,y[i]-1})){
					int B=Y[{x[i]-1,y[i]-1}];
					add_edge(A,B,x[i]-1,y[i]-1);
					Y.erase({x[i]-1,y[i]-1});
				}
				else{
					Y[{x[i]-1,y[i]-1}]=A;
				}
				if(Y.count({x[i]+1,y[i]-1})){
					int B=Y[{x[i]+1,y[i]-1}];
					add_edge(A,B,x[i]+1,y[i]-1);
					Y.erase({x[i]+1,y[i]-1});
				}
				else{
					Y[{x[i]+1,y[i]+1}]=A;
				}
			}
		}
	}
	if(sz[f(0)]<n) return 0;
	int m=u.size();
	vector<int> used(m);
	function<void(int)> dfs=[&](int x){
		used[x]=1;
		for(auto [it,A,B]:g[x]){
			if(used[it]) continue;
			a[it]=A;
			b[it]=B;
			dfs(it);
		}
	};
	for(auto [it,A]: Y){
		if(used[A]) continue;
		a[A]=it.fr;
		b[A]=it.sc;
		dfs(A);
	}
	for(int i=0;i<m;i++){
		if(used[i]) continue;
		a[i]=g[i].back()[1];
		b[i]=g[i].back()[2];
		g[i].pop_back();
		dfs(i);
	}
	build(u,v,a,b);
	return 1;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30