Submission #827208

#	Time	Username	Problem	Language	Result	Execution time	Memory
827208		Sohsoh84	Fountain Parks (IOI21_parks)	C++17	5 / 100	489 ms	43536 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pll;

#define all(x)		(x).begin(), (x).end()
#define X		first
#define Y		second
#define sep		' '
#define debug(x)	cerr << #x << ": " << x << endl;

const int MAXN = 1e6 + 10;
const int DX[4] = {-1, 0, 1, 0};
const int DY[4] = {0, -1, 0, 1};

namespace answer {
	vector<int> u, v, a, b;
}

vector<pair<pll, int>> edges;

int X[MAXN], Y[MAXN], par[MAXN], n;
map<pll, int> mp;

int find(int v) {
	return par[v] == v ? v : par[v] = find(par[v]);
}

inline bool unite(int u_, int v_) {
	int u = find(u_), v = find(v_);
	if (u == v) return false;

	edges.push_back({{u_, v_}, (int)answer::u.size()});

	answer::u.push_back(u_);
	answer::v.push_back(v_);
	par[u] = v;

	return true;
}

int construct_roads(vector<int> x_, vector<int> y_) {
	n = x_.size();
	for (int i = 0; i < n; i++) {
		X[i] = x_[i];
		Y[i] = y_[i];

		mp[pll(X[i], Y[i])] = i;
		par[i] = i;
	}

	int edg = 0;
	vector<int> vert_vec;
	for (int i = 0; i < n; i++) vert_vec.push_back(i);
	sort(all(vert_vec), [] (int i, int j) {
		return Y[i] < Y[j];
	});

	for (int i = 0; i < 4; i++) {
		for (int tv = 0; tv < n; tv++) {
			int v = vert_vec[tv];

			int ux = X[v] + 2 * DX[i], uy = Y[v] + 2 * DY[i];
			auto it = mp.find(pll(ux, uy));
			if (it == mp.end()) continue;

			int u = it -> second;	
			edg += unite(u, v);
		}
	}

	if (edg < n - 1) return 0;
	sort(all(edges));

	set<pll> st;
	answer::a.resize(n - 1);
	answer::b.resize(n - 1);

	for (int ti = 0; ti < n - 1; ti++) {
		int i = edges[ti].Y;

//		cerr  << answer::u[i] << sep << answer::v[i] << endl;
		if (X[answer::u[i]] == X[answer::v[i]]) {
			int tx = X[answer::u[i]] - 1, ty = (Y[answer::u[i]] + Y[answer::v[i]]) / 2;	
			if (st.find(pll(tx, ty)) == st.end()) {
				st.insert(pll(tx, ty));
				answer::a[i] = tx;	
				answer::b[i] = ty;	
				continue;
			}

			tx += 2;
			if (st.find(pll(tx, ty)) == st.end()) {
				st.insert(pll(tx, ty));
				answer::a[i] = tx;	
				answer::b[i] = ty;	
				continue;
			}

			return 0;
		} else {
			int ty = Y[answer::u[i]] - 1, tx = (X[answer::u[i]] + X[answer::v[i]]) / 2;	
			if (st.find(pll(tx, ty)) == st.end()) {
				st.insert(pll(tx, ty));
				answer::a[i] = tx;	
				answer::b[i] = ty;	
				continue;
			}

			ty += 2;
			if (st.find(pll(tx, ty)) == st.end()) {
				st.insert(pll(tx, ty));
				answer::a[i] = tx;	
				answer::b[i] = ty;	
				continue;
			}

			return 0;
		}
	}

	build(answer::u, answer::v, answer::a, answer::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