Submission #642317

#	Time	Username	Problem	Language	Result	Execution time	Memory
642317		dozer	Joker (BOI20_joker)	C++14	25 / 100	94 ms	46328 KiB

Joker

#include <bits/stdc++.h>
using namespace std;
#define fileio() freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define sp " "
#define endl "\n"
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define N 400005

const int modulo = 1e9 + 7;
int ans[N], u[N], v[N], l[N], r[N], n;
vector<int> ind[N], root, gh[N];
map<int, int> res[N];

int find(vector<int> &b, int node)
{
	if (node < 0) return -(find(b, -node));
	if (node == b[node]) return node;
	if (node == -b[node]) return 0;
	return b[node] = find(b, b[node]);
}


int32_t main()
{
	fastio();


	int m, q;
	cin>>n>>m>>q;
	root.resize(n + 5, 0);
	for (int i = 1; i <= n; i++)
		root[i] = i;

	for (int i = 1; i <= m; i++)
	{
		cin>>u[i]>>v[i];
	}

	for (int i = 1; i <= q; i++)
	{
		cin>>l[i]>>r[i];
		ind[r[i]].pb(l[i]);
	}

	for (int i = m; i >= 1; i--)
	{
		/*
		if (ind[i].size() > 0)
		{
			for (auto j : root) gh[i].pb(j);
		}
		*/
		if (ans[i] == 1) 
		{
			ans[i - 1] = 1;
			continue;
		}
		int a = find(root, u[i]), b = find(root, v[i]);
		if (a == b) 
		{
			ans[i - 1] = 1;
		}
		else
		{
			if (a < 0) a *= -1, b *= -1;
			root[a] = -b;
		}
		//cout<<i<<sp<<ans[i]<<endl;
	}
/*
	for (int i = m; i >= 1; i--)
	{
		sort(ind[i].begin(), ind[i].end());
		if (gh[i].empty() || ans[i] == 1) continue;
		int last = 1;
		for (auto j : ind[i])
		{
			if (res[i][last] == 1) 
			{
				res[i][j] = 1;
				last = j;
				continue;
			}
			for (int k = last; k < j; k++)
			{
				int a = find(gh[i], u[k]), b = find(gh[i], v[k]);
				if (a == b)
				{
					res[i][j] = 1;
					break;
				} 
				if (a < 0) a *= -1, b *= -1;
				gh[i][a] = -b;
			}
			last = j;
		}
	}
*/
	for (int i = 1; i <= q; i++)
	{
		//if (res[r[i]][l[i]] || ans[r[i]]) cout<<"YES\n";
		if (ans[r[i]]) cout<<"YES\n";
		else cout<<"NO\n";
	}
	cerr<<"time taken : "<<(float)clock() / CLOCKS_PER_SEC<<" seconds\n";
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 8
• Subtask 3: 25 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29