Submission #567546

#	Time	Username	Problem	Language	Result	Execution time	Memory
567546		PiejanVDC	Fountain Parks (IOI21_parks)	C++17	55 / 100	959 ms	37436 KiB

parks

#include <bits/stdc++.h>
#include "parks.h"
using namespace std;
 
void build(vector<int>u, vector<int>v, vector<int>a, vector<int>b);
 
int construct_roads(std::vector<int> xx, std::vector<int> yy) {
	const int n = (int)xx.size();
	set<pair<int,int>>s;
	set<pair<int,int>>t;
	map<pair<int,int>,int>id;

	for(int i = 0 ; i < n ; i++)
		s.insert({xx[i], yy[i]}), id[{xx[i], yy[i]}] = i;

	int F,S;

	for(int i = 0 ; i < n ; i++) {
		if(!s.count({xx[i]-2, yy[i]}))
			F = xx[i], S = yy[i];
	}

	queue<pair<pair<int,int>, int>>st;
	st.push({{F, S}, 0});
	
	s.erase(s.find({F, S}));

	vector<int>u,v,a,b;

	auto process = [&] (int X, int Y, int T) -> void {
		s.erase(s.find({X,Y}));
		u.push_back(id[{X,Y}]);
		st.push({{X, Y}, T});
		if(T == 0) {
			v.push_back(id[{X-2,Y}]);
			if(!t.count({X-1, Y+1}))
				t.insert({X-1, Y+1}), a.push_back(X-1), b.push_back(Y+1);
			else
				t.insert({X-1, Y-1}), a.push_back(X-1), b.push_back(Y-1);
		} else if(T == 1) {
			v.push_back(id[{X,Y+2}]);
			if(!t.count({X+1, Y+1}))
				t.insert({X+1, Y+1}), a.push_back(X+1), b.push_back(Y+1);
			else
				t.insert({X-1, Y+1}), a.push_back(X-1), b.push_back(Y+1);
		} else if(T == 2) {
			v.push_back(id[{X+2,Y}]);
			if(!t.count({X+1, Y-1}))
				t.insert({X+1, Y-1}), a.push_back(X+1), b.push_back(Y-1);
			else
				t.insert({X+1, Y+1}), a.push_back(X+1), b.push_back(Y+1);
		} else {
			v.push_back(id[{X,Y-2}]);
			if(!t.count({X-1, Y-1}))
				t.insert({X-1, Y-1}), a.push_back(X-1), b.push_back(Y-1);
			else
				t.insert({X+1, Y-1}), a.push_back(X+1), b.push_back(Y-1);
		}
	};
	int cnt = 0;
	while(!st.empty()) {
		auto [x,y] = st.front().first;
		int d = st.front().second;
		st.pop();
		cnt++;
		if(d == 0) {
			if(s.count({x, y+2})) {
				process(x, y+2, 3);
				if(s.count({x+2, y}))
					process(x+2, y, 0);
				if(s.count({x, y-2}))
					process(x, y-2, 1);
			} else {
				if(s.count({x, y-2}))
					process(x, y-2, 1);
				if(s.count({x+2, y}))
					process(x+2, y, 0);
			}
		} else if(d == 1) {
			if(s.count({x+2, y})) {
				process(x+2, y, 0);
				if(s.count({x, y-2}))
					process(x, y-2, 1);
				if(s.count({x-2, y}))
					process(x-2, y, 2);
			} else {
				if(s.count({x-2, y}))
					process(x-2, y, 2);
				if(s.count({x, y-2}))
					process(x, y-2, 1);
			}
		} else if(d == 2) {
			if(s.count({x, y-2})) {
				process(x, y-2, 1);
				if(s.count({x-2, y}))
					process(x-2, y, 2);
				if(s.count({x, y+2}))
					process(x, y+2, 3);
			} else {
				if(s.count({x, y+2}))
					process(x, y+2, 3);
				if(s.count({x-2, y}))
					process(x-2, y, 2);
			}
		} else {
			if(s.count({x-2, y})) {
				process(x-2, y, 2);
				if(s.count({x, y+2}))
					process(x, y+2, 3);
				if(s.count({x+2, y}))
					process(x+2, y, 0);
			} else {
				if(s.count({x+2, y}))
					process(x+2, y, 0);
				if(s.count({x, y+2}))
					process(x, y+2, 3);
			}
		}
	}

	if(cnt < n)
		return 0;
	build(u,v,a,b);
	return 1;
}

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