Submission #1087140

#	Time	Username	Problem	Language	Result	Execution time	Memory
1087140		dubabuba	Tropical Garden (IOI11_garden)	C++14	0 / 100	7 ms	15196 KiB

garden

#include <bits/stdc++.h>
#include "garden.h"
#include "gardenlib.h"

using namespace std;

const int mxn = 1.5e5 + 1000;
const int MXN = 3e5 + 100000;
typedef pair<int, int> pii;
#define ff first
#define ss second
#define MP make_pair

vector<int> adj[mxn]; // OG graph
vector<int> rev[MXN]; // buba graph
int dis[MXN], nxt[MXN];
bool vis[MXN];

bool fake(int cur, int prv) {
	if(adj[cur].size() == 1) return 0;
	return prv == adj[cur][0];
}

void build_buba(int cur, int prv) {
	int bu = cur + mxn * fake(cur, prv);
	// cout << prv << " -> " << cur << " (" << fake(cur, prv) << ")\n";

	if(vis[bu]) return;
	vis[bu] = 1;
	
	int sus = 0;
	if(adj[cur].size() == 1) sus = adj[cur][0];
	else if(prv == adj[cur][0]) sus = adj[cur][1];
	else sus = adj[cur][0];

	int bv = sus + mxn * fake(sus, cur);
	nxt[bu] = bv;
	rev[bv].push_back(bu);

	build_buba(sus, cur);
}

void count_routes(int N, int M, int P, int R[][2], int Q, int G[]) {
	P++;
	for(int i = 0; i < M; i++) {
		int u = R[i][0] + 1;
		int v = R[i][1] + 1;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}

	// for(int i = 1; i <= N; i++) {
	// 	cout << i << ": ";
	// 	for(int j : adj[i])
	// 		cout << j << ' ';
	// 	cout << endl;
	// }

	for(int i = 1; i <= N; i++)
		build_buba(i, 0);
	memset(vis, 0, sizeof vis);
	
	vector<int> path, cyc;
	int node = 1;
	while(!vis[node]) {
		vis[node] = 1;
		path.push_back(node);
		node = nxt[node];
	}

	// cout << "path: ";
	// for(int u : path)
	// 	cout << u << ' ';
	// cout << endl;
	// cout << "node = " << node << endl;

	while(path.back() != node) {
		int u = path.back();
		cyc.push_back(u);
		path.pop_back();
	}
	cyc.push_back(node);

	// cout << "cyc: ";
	// for(int u : cyc)
	// 	cout << u << ' ';
	// cout << endl << "size = " << cyc.size() << endl;

	priority_queue<pii> pq;
	pq.push(MP(0, P));

	memset(dis, -1, sizeof dis);

	while(pq.size()) {
		int d = -pq.top().ff;
		int u = pq.top().ss;
		pq.pop();

		if(dis[u] > -1) continue;
		dis[u] = d;

		for(int v : rev[u])
			if(!dis[v] && v != P)
				pq.push(MP(-d-1, v));
	}

	for(int i = 0; i < Q; i++) {
		int D = G[i], ans = 0;
		for(int u = 1; u <= N; u++) {
			if(dis[u] == -1) continue;
			if(dis[u] > D) continue;
			int extra = dis[u] - D;
			if(extra % cyc.size() == 0)
				ans++;
		}
		answer(ans);
	}
}

• Subtask 1: 0 / 49
• Subtask 2: 0 / 20
• Subtask 3: 0 / 31