Submission #254682

#	Time	Username	Problem	Language	Result	Execution time	Memory
254682		Mahdi_Jfri	Bridges (APIO19_bridges)	C++14	73 / 100	3022 ms	24844 KiB

bridges

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back
#define lb(a) ((a)&(-(a)))

const int maxn = 1e5 + 20;
const int sq = 1000;

int from[maxn] , to[maxn] , w[maxn];

bool has[maxn];

int e[maxn] , nw[maxn] , s[maxn] , tmpw[maxn] , ans[maxn] , type[maxn];

vector<int> edges[maxn * 2] , query[maxn * 2];

vector<pair<int , int> > history;

int par[maxn / 2];

int root(int v , bool compress = 1)
{
	if(compress)
		return (par[v] < 0? v : par[v] = root(par[v]));

	while(par[v] >= 0)
		v = par[v];
	return v;
}

void merge(int a , int b , bool save = 0 , bool compress = 1)
{
	a = root(a , compress) , b = root(b , compress);

	if(a == b)
	{
		if(save)
			history.pb({-1 , -1});
		return;
	}

	if(-par[a] < -par[b])
		swap(a , b);
	
	if(save)
		history.pb({par[b] , b});
	par[a] += par[b];
	par[b] = a;
}

void undo()
{
	auto tmp = history.back();
	history.pop_back();

	if(tmp.second == -1)
		return;

	int b = tmp.second;
	int a = par[b];

	par[b] = tmp.first;
	par[a] -= par[b];
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	
	int n , m;
	cin >> n >> m;

	vector<int> cmp;
	for(int i = 0; i < m; i++)
	{
		int a , b;
		cin >> a >> b >> w[i];
		a-- , b--;

		from[i] = a , to[i] = b;
		cmp.pb(w[i]);
	}

	int q;
	cin >> q;

	for(int i = 0; i < q; i++)
	{
		cin >> type[i];
		if(type[i] == 1)
		{
			cin >> e[i] >> nw[i];
			e[i]--;
		}
		else
		{
			cin >> s[i] >> nw[i];
			s[i]--;
		}
		cmp.pb(nw[i]);
	}

	sort(cmp.begin() , cmp.end());
	cmp.resize(unique(cmp.begin() , cmp.end()) - cmp.begin());

	for(int i = 0; i < m; i++)
		w[i] = lower_bound(cmp.begin() , cmp.end() , w[i]) - cmp.begin();

	for(int i = 0; i < q; i++)
		nw[i] = lower_bound(cmp.begin() , cmp.end() , nw[i]) - cmp.begin();

	for(int l = 0; l < q; l += sq)
	{
		memset(has , 0 , sizeof has);
		memset(par , -1 , sizeof par);

		int sz = min(sq , q - l);
		vector<int> tmp;
		for(int i = l; i < l + sz; i++)
		{
			if(type[i] == 1)
				has[e[i]] = 1 , tmp.pb(e[i]);
			else
				query[nw[i]].pb(i);
		}

		for(int i = 0; i < m; i++)
			if(!has[i])
				edges[w[i]].pb(i);

		sort(tmp.begin() , tmp.end());
		tmp.resize(unique(tmp.begin() , tmp.end()) - tmp.begin());

		for(int i = (int)cmp.size() - 1; i >= 0; i--)
		{
			for(auto e : edges[i])
				merge(from[e] , to[e]);

			for(auto ind : query[i])
			{
				for(auto e : tmp)
					tmpw[e] = w[e];
				for(int j = l; j < ind; j++)
					if(type[j] == 1)
						tmpw[e[j]] = nw[j];

				int sz = 0;
				for(auto e : tmp)
					if(tmpw[e] >= i)
					{
						merge(from[e] , to[e] , 1 , 0);
						sz++;
					}

				ans[ind] = -par[root(s[ind] , 0)];

				while(sz--)
					undo();
			}

			edges[i].clear();
			query[i].clear();
		}

		for(int i = l; i < l + sz; i++)
			if(type[i] == 1)
				w[e[i]] = nw[i];
	}

	for(int i = 0; i < q; i++)
		if(type[i] == 2)
			cout << ans[i] << endl;
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 0 / 27