Submission #1039825

#	Time	Username	Problem	Language	Result	Execution time	Memory
1039825		vjudge1	Fountain Parks (IOI21_parks)	C++17	15 / 100	222 ms	39592 KiB

parks

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

struct dsu {
	vector<int> e;
	int cc;
	dsu(int n) {
		cc=n;
		e=vector<int> (n, -1);
	}
	int get(int a) {
		if(e[a] < 0)return a;
		return e[a] = get(e[a]);
	}
	bool unite(int a, int b) {
		a=get(a), b=get(b);
		if(a==b)return false;
		cc--;
		if(-e[a] > -e[b])swap(a, b);
		e[b]+=e[a];
		e[a]=b;
		return true;
	}
};
int construct_roads(std::vector<int> x, std::vector<int> y) {
	vector<vector<int>> p(7);
	int n = x.size();
	map<pair<int,int>, int> mp;
	for(int i = 0;i<n;i++) {
		mp[{x[i], y[i]}]=i;
		p[x[i]].push_back(i);
	}
	dsu d(n);
	vector<int> u, v;
	for(int i= 0;i<7;i++) {
		sort(p[i].begin(), p[i].end(), [&](int a, int b) {
					return y[a] < y[b];
				});
	}
	{
		int i = 6;
		for(int j = 1;j<(int)p[i].size();j++) {
			if(y[p[i][j]] == y[p[i][j-1]] + 2){
				if(d.unite(p[i][j], p[i][j-1])) {
					v.push_back(p[i][j]);
					u.push_back(p[i][j-1]);
				}
			}
		}
	}
	{
		int i = 2;
		for(int j = 1;j<(int)p[i].size();j++) {
			if(y[p[i][j]] == y[p[i][j-1]] + 2){
				if(d.unite(p[i][j], p[i][j-1])) {
					v.push_back(p[i][j]);
					u.push_back(p[i][j-1]);
				}
			}
		}
	}
	{
		int i = 4;
		for(int j = 1;j<(int)p[i].size();j++) {
			if(y[p[i][j]] == y[p[i][j-1]] + 2){
				if(d.unite(p[i][j], p[i][j-1])) {
					v.push_back(p[i][j]);
					u.push_back(p[i][j-1]);
				}
			}
		}
	}
	{
		for(int j:p[4]) {
			if(mp.find({x[j]-2, y[j]}) != mp.end() and d.unite(j, mp[{x[j]-2, y[j]}])) {
				u.push_back(mp[{x[j]-2, y[j]}]);
				v.push_back(j);
			}
		}
		for(int j:p[4]) {
			if(mp.find({x[j]+2, y[j]}) != mp.end() and d.unite(j, mp[{x[j]+2, y[j]}])) {
				v.push_back(mp[{x[j]+2, y[j]}]);
				u.push_back(j);
			}
		}
	}
//	for(int i = 0;i<(int)v.size();i++) {
//		cout << u[i] << " "<< v[i] << endl;
//	}
	vector<int> a, b;
	if(d.cc != 1)return 0;
	map<pair<int,int>, bool> used;
	for(int j = 0;j<n-1;j++) {
		if(x[u[j]] == x[v[j]]) {
			if(x[u[j]] == 2) {
				a.push_back(x[u[j]]-1);
				b.push_back(y[u[j]]+1);
				used[{x[u[j]]-1,y[u[j]]+1}]=1;
			}
			else if(x[u[j]] == 6) {
				a.push_back(x[u[j]]+1);
				b.push_back(y[u[j]]+1);
				used[{x[u[j]]+1,y[u[j]]+1}]=1;
			}
			else if(x[u[j]] == 4)  {
				a.push_back(-1);
				b.push_back(-1);
			}
		}
		else if(x[u[j]] == 2) {
			a.push_back(x[u[j]]+1);
			b.push_back(y[u[j]]+1);
			used[{x[u[j]]+1, y[u[j]]+1}]=1;
		} else if(x[u[j]] == 4) {
			a.push_back(x[u[j]]+1);
			b.push_back(y[u[j]]-1);
			used[{x[u[j]]+1, y[u[j]]-1}]=1;
		}
	}
	for(int j = 0;j<n-1;j++) {
		if(a[j] == -1) {
			if(!used[{x[u[j]]-1, y[u[j]]+1}]) {
				a[j] = x[u[j]]-1;
				b[j] = y[u[j]]+1;
				used[{x[u[j]]-1, y[u[j]]+1}]=1;
			}
			else if(!used[{x[u[j]]+1, y[u[j]]+1}]) {
				a[j] = x[u[j]]+1;
				b[j] = y[u[j]]+1;
				used[{x[u[j]]+1, y[u[j]]+1}]=1;
			}
			else {
				return 0;
			}
		}
	}
	build(u, v, a, b);
	return 1;
}

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