Submission #434491

#	Time	Username	Problem	Language	Result	Execution time	Memory
434491		frodakcin	Comparing Plants (IOI20_plants)	C++11	0 / 100	68 ms	6084 KiB

plants

#include "plants.h"
#include <queue>
#include <bitset>

const int MN = 5e3+10;
const int INF = 0x3f3f3f3f;

int N, K, ts[MN], ctr;
bool v[MN];
std::vector<int> a[MN]; // i > a[i][...] -- dag
std::bitset<MN> vis[MN];

void dfs(int n)
{
	v[n]=1;
	for(int x:a[n])
		if(!v[x])
			dfs(x);
	ts[ctr++]=n;
}

void init(int k, std::vector<int> r) {
	K=k, N=r.size();
	
	std::queue<int> q;
	int zc=0;
	for(int i=N-K;i<N;++i)
		zc += !r[i];
	for(int i=0;i<N;++i)
	{
		zc -= !r[(N-K+i)%N];
		if(zc==0 && r[i]==0)
			q.push(i);
		zc += !r[i];
	}

	for(;!q.empty();)
	{
		int n=q.front(); q.pop();
		
		// check
		bool ok=1;
		for(int i=1;i<K;++i)
			if(r[(n-i+N)%N]==0)
				ok=0;
		if(!ok) continue;

		// add
		r[n]=INF;
		for(int i=K-1;i>0;--i)
			--r[(n-i+N)%N];
		for(int i=1;i<K;++i)
			if(r[(n+i)%N]==0)
			{
				a[n].push_back((n+i)%N);
				q.push((n+i)%N);
				break;
			}
		for(int i=K-1;i>0;--i)
			if(r[(n-i+N)%N]==0)
			{
				a[n].push_back((n-i+N)%N);
				q.push((n-i+N)%N);
				break;
			}
	}

	for(int i=0;i<N;++i)
		if(!v[i])
			dfs(i);

	for(int i=0;i<N;++i)
		vis[i].set(i);
	for(int i=0;i<N;++i)
		for(int x:a[ts[i]])
			vis[ts[i]]|=vis[x];
	return;
}

int compare_plants(int x, int y)
{
	if(vis[x][y]) return 1;
	if(vis[y][x]) return -1;
	return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 14
• Subtask 3: 0 / 13
• Subtask 4: 0 / 17
• Subtask 5: 0 / 11
• Subtask 6: 0 / 15
• Subtask 7: 0 / 25