Submission #547376

#	Time	Username	Problem	Language	Result	Execution time	Memory
547376		blue	Reconstruction Project (JOI22_reconstruction)	C++17	100 / 100	3472 ms	35132 KiB

reconstruction

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <cassert>
using namespace std;

using ll = long long;
using vll = vector<ll>;
using vi = vector<int>;
using vvi = vector<vi>;
using pll = pair<ll, ll>;
#define sz(x) int(x.size())

struct edge
{
	int a;
	int b;
	ll w;
};

bool operator < (edge A, edge B)
{
	return A.w < B.w;
}

struct costchange
{
	ll w;
	ll deltaX;
	ll deltaC;
};

bool operator < (costchange A, costchange B)
{
	return A.w < B.w;
}



const int maxM = 100'000;
const int maxN = 500;

vi A(maxM), B(maxM), W(maxM);




set<int> adj[maxN];

void addedge(int e)
{
	adj[A[e]].insert(e);
	adj[B[e]].insert(e);
}

void removeedge(int e)
{
	adj[A[e]].erase(e);
	adj[B[e]].erase(e);
}

vi vis; //done
vi cyclic; //done

vi st; //done

vi paredge;

bool discovered;

void dfs(int u, int pe)
{
	// cerr << "\n\n\n\n";
	// cerr << "enter : dfs " << u << ' ' << p << '\n';
	vis[u] = 1;

	st.push_back(u);
	for(int e : adj[u])
	{
		// cerr << "enter edge\n";
		int v = A[e] + B[e] - u;

		// cerr << u << " -> " << v << '\n';
		if(e == pe) 
		{
			// cerr << "case 1\n";
			continue;
		}
		else if(vis[v])
		{
			if(!discovered)
			{
				discovered = 1;
				// cerr << "case 2\n";

				// cerr << "paredge v = " << paredge[v] << '\n';
				// for(int f : st) cerr << "f = " << f << " : " << paredge[f] << '\n';

				for(int k = sz(st) - 1; k >= 0 && st[k] != v; k--)
				{
					// cerr << "checking : k = " << k << '\n';
					// if(paredge[st[k]] == -1) cerr << "ATTENTION : V = " << v << '\n'; 
					cyclic.push_back(paredge[st[k]]);
				}
				cyclic.push_back(e);
				// cerr << "case 2 done\n";
			}
			
		}
		else
		{
			// cerr << "case 3\n";
			paredge[v] = e;
			dfs(v, e);
			if(discovered) return;
		}

	}
	st.pop_back();
}








int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	int N, M;
	cin >> N >> M;

	// assert(M*N <= 50'000'000 - 1);

	vector<edge> E(M);
	for(int j = 0; j < M; j++)
	{
		cin >> E[j].a >> E[j].b >> E[j].w;
		E[j].a--;
		E[j].b--;
	}
	sort(E.begin(), E.end());

	for(int j = 0; j < M; j++)
	{
		A[j] = E[j].a;
		B[j] = E[j].b;
		W[j] = E[j].w;
	}

	// cerr << "\n\n\n edges = \n";
	// for(int j = 0; j < M; j++) cerr << A[j] << ' ' << B[j] << ' ' << W[j] << '\n';
	// 	cerr << "\n\n";



	for(int i = 0; i < N; i++)
		adj[i].clear();

	vi edgelist;


	vll minW(M), maxW(M); //do 2x the actual thing!!!

	for(int j = 0; j < M; j++)
	{
		// cerr << "\n\n\n\n\n\n\n";
		// cerr << "j = " << j << '\n';
		vis = vi(N, 0);
		assert(sz(edgelist) < N);

		// edgelist.push_back(j);
		addedge(j);


		// cerr << "edgelist : \n";
		// for(int e : edgelist)
		// 	cerr << A[e] << ' ' << B[e] << ' ' << W[e] << '\n';

		// cerr << "###\n";
		// adj = vvi(N);
		// for(int e : edgelist)
		// {
		// 	adj[A[e]].push_back(e);
		// 	adj[B[e]].push_back(e);
		// }

		cyclic.clear();

		discovered = 0;

		st.clear();

		paredge = vi(N, -1);

		// cerr << "done\n";

		for(int i = 0; i < N; i++)
		{
			if(vis[i]) continue;
			if(discovered) break;
			dfs(i, -1);
		}

		// cerr << "dfs done\n";

		if(cyclic.empty()) minW[j] = 0;
		else
		{
			// cerr << "!!!!!CYCLIC DETECTED!!!!!\n";
			// cerr << "case = 2" << '\n';

			int mincyclic = cyclic[0];
			for(int c : cyclic)
				mincyclic = min(mincyclic, c);

			removeedge(mincyclic);
			// cerr << "# done\n";

			// cerr << "mincyclic = " << mincyclic << '\n';

			minW[j] = W[j] + W[mincyclic];

			// cerr << "transition from " << mincyclic << " to " << j << " = " << minW[j] << "/2" << '\n';

			// cerr << "3 done\n";
		}

		// cerr << "J = " << j << " done\n";
	}






























	// cerr << "check\n";
	// cerr << "\n\n\n\n\n\n\n\nPART 2 PART 2 PART 2\n";


	// edgelist.clear();

	for(int i = 0; i < N; i++)
		adj[i].clear();

	for(int j = M-1; j >= 0; j--)
	{
		// cerr << "\n\n\n\n\n\n\n";
		// cerr << "j = " << j << '\n';
		vis = vi(N, 0);
		assert(sz(edgelist) < N);

		// edgelist.push_back(j);
		addedge(j);

		// cerr << "edgelist : \n";
		// for(int e : edgelist)
		// 	cerr << A[e] << ' ' << B[e] << ' ' << W[e] << '\n';

		// cerr << "###\n";
		// adj = vvi(N);
		// for(int e : edgelist)
		// {
		// 	adj[A[e]].push_back(e);
		// 	adj[B[e]].push_back(e);
		// }

		cyclic.clear();

		discovered = 0;

		st.clear();

		paredge = vi(N, -1);

		// cerr << "done\n";

		for(int i = 0; i < N; i++)
		{
			if(vis[i]) continue;
			if(discovered) break;
			dfs(i, -1);
		}

		// cerr << "dfs done\n";

		if(cyclic.empty()) maxW[j] = 2'000'000'004;
		else
		{
			// cerr << "!!!!!CYCLIC DETECTED!!!!!\n";
			// cerr << "case = 2" << '\n';
			// vi nwedgelist;

			int maxcyclic = cyclic[0];
			for(int c : cyclic)
				maxcyclic = max(maxcyclic, c);

			// cerr << "1 done\n";

			// for(int e : edgelist)
			// 	if(e != maxcyclic)
			// 		nwedgelist.push_back(e);
			removeedge(maxcyclic);

			// cerr << "2 done\n";

			// edgelist = nwedgelist;

			// cerr << "# done\n";

			maxW[j] = W[j] + W[maxcyclic];

			// cerr << "3 done\n";
		}

		// cerr << "J = " << j << " done\n";
	}


	// for(int j = 0; j < M; j++) cerr << A[j] << ' ' << B[j] << ' ' << W[j] << " : " << minW[j] << ' ' << maxW[j] << '\n';


	vector<pll> deltaX, deltaC;

	for(int j = 0; j < M; j++)
	{
		deltaX.push_back({minW[j], -1});
		deltaC.push_back({minW[j], W[j]});

		deltaX.push_back({2*W[j], +1});
		deltaC.push_back({2*W[j], -W[j]});

		deltaX.push_back({2*W[j]+1, +1});
		deltaC.push_back({2*W[j]+1, -W[j]});

		deltaX.push_back({maxW[j], -1});
		deltaC.push_back({maxW[j], +W[j]});
	}

	sort(deltaX.begin(), deltaX.end());
	sort(deltaC.begin(), deltaC.end());


	ll currX = 0, currC = 0;

	int it = -1;

	int Q;
	cin >> Q;

	for(int q = 0; q < Q; q++)
	{
		ll X;
		cin >> X;

		while(it+1 < sz(deltaX) && deltaX[it+1].first <= 2*X)
		{
			it++;
			currX += deltaX[it].second;
			currC += deltaC[it].second;
		}

		cout << currX*X + currC << '\n';
	}
}

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 7 / 7
• Subtask 4: 28 / 28
• Subtask 5: 35 / 35
• Subtask 6: 23 / 23