Submission #481532

#	Time	Username	Problem	Language	Result	Execution time	Memory
481532		8e7	Fountain Parks (IOI21_parks)	C++17	5 / 100	624 ms	81504 KiB

parks

//Challenge: Accepted
#include "parks.h"
#include <iostream>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
#include <utility>
#include <queue>
#include <vector>
#include <assert.h>
using namespace std;
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ...b) {
	cout << a << " ", debug(b ...);
};
template<class T> void pary (T l, T r) {
	while (l!= r) cout << *l << " ", l++;
	cout << endl;
};
#define ll long long
#define maxn 200005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
unordered_map<ll, vector<int> > ed;
unordered_map<int, vector<ll> > cor;
unordered_map<ll, int> mp;
struct pnt{
	int x, y, id;
	pnt(){x = y = id = 0;}
	pnt(int a, int b, int c){x = a, y = b, id = c;}
};
ll ha(pii p) {
	return ((ll)p.ff<<20) + p.ss;	
}
pii getv(ll h) {
	return {h>>20, h & ((1<<20) - 1)};
}

int par[maxn];
int find(int a) {
	return a == par[a] ? a : par[a] = find(par[a]);
}
int num = 0;
bool Union (int a, int b) {
	//debug(a, b);
	a = find(a), b = find(b);
	if (a == b) return false;
	//debug(1);
	num--;
	par[find(a)] = find(b);
	return true;
}
int construct_roads(std::vector<int> x, std::vector<int> y) {
	int n = x.size();
	for (int i = 1;i <= n;i++) par[i] = i;
	num = n;
	vector<pnt> a;
	for (int i = 0;i < n;i++) {
		a.push_back(pnt(x[i], y[i], i+1));
		mp[ha({x[i], y[i]})] = i+1;
	}
    if (x.size() == 1) {
		build({}, {}, {}, {});
        return 1;
    }
    vector<int> u, v, ax, ay;
	int id = 0;
	for (int i = 0;i < n;i++) {
		pii p1 = {a[i].x + 2, a[i].y}, p2 = {a[i].x, a[i].y + 2};
		int v1 = mp[ha(p1)], v2 = mp[ha(p2)];
		if (v1) {
			u.push_back(a[i].id-1), v.push_back(v1-1);		
			pii h1 = {a[i].x + 1, a[i].y + 1}, h2 = {a[i].x + 1, a[i].y - 1};
			ed[ha(h1)].push_back(id), ed[ha(h2)].push_back(id);
			cor[id].push_back(ha(h1)), cor[id].push_back(ha(h2));
			id++;
		}
		if (v2) {
			u.push_back(a[i].id-1), v.push_back(v2-1);
			pii h1 = {a[i].x + 1, a[i].y + 1}, h2 = {a[i].x - 1, a[i].y + 1};
			ed[ha(h1)].push_back(id), ed[ha(h2)].push_back(id);
			cor[id].push_back(ha(h1)), cor[id].push_back(ha(h2));
			id++;
		}
	}
	//debug(111);
	if (id != n - 1) return 0;
	ax.resize(id), ay.resize(id);
	for (int i = 0;i < id;i++) ax[i] = ay[i] = 0;
	queue<ll> que;
	while (true) {
		bool f = 0;
		for (auto i:ed) {
			if (i.ss.size()) que.push(i.ff), f = 1;	
		}
		if (!f) break;
		while (que.size()) {
			ll h = que.front();
			pii cur = getv(que.front());que.pop();
			if (ed[h].size() == 0) continue;
			int ans = ed[h].back();
			ax[ans] = cur.ff, ay[ans] = cur.ss;
			ed[h].clear();
			//debug(cur.ff, cur.ss, ans, h);
			for (auto x:cor[ans]) {
				auto it = find(ed[x].begin(), ed[x].end(), ans);
				if (it != ed[x].end()) {
					ed[x].erase(it);
					if (ed[x].size() == 1) {
						que.push(x);
					}
				}
			}
		}
	}
	//sort(a.begin(), a.end(), [&](pnt p, pnt q){return (p.x == q.x ? p.y < q.y : p.x < q.x);});
	//sort(b.begin(), b.end(), [&](pnt p, pnt q){return (p.x == q.x ? p.y < q.y : p.x < q.x);});
	//assert(cnt == id);
	for (auto i:ed) assert(i.ss.size() == 0);
	build(u, v, ax, ay);
    return 1;
}
/*
5
2 2
4 2
4 4
4 6
2 6
*/

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