Submission #533732

#	Time	Username	Problem	Language	Result	Execution time	Memory
533732		1bin	Road Closures (APIO21_roads)	C++14	5 / 100	238 ms	50032 KiB

roads

#include <bits/stdc++.h>
#include <cassert>

using namespace std;

#define all(v) v.begin(), v.end()
typedef long long ll;
const int NMAX = 1e5 + 5;
set<pair<ll, ll>> adj[NMAX];
int dg[NMAX], vis[NMAX], e[NMAX];
ll dp[NMAX][2], Sum[NMAX];
vector<int> D[NMAX];
set<int> X;
multiset<ll> C[NMAX], L[NMAX], R[NMAX];

/*
5
0 1 1
0 2 4
0 3 3
2 4 2
*/

/*
4
0 1 5
0 3 5
0 2 10
*/
void dfs(int now, int k) {
	vis[now] = 1;

	while (e[now] - dg[now] > L[now].size() && R[now].size()) {
		assert(R[now].size());
		auto it = R[now].begin();
		//cout << "put : " << now << ' ' << *it << '\n';
		L[now].emplace(*it);  Sum[now] += *it;
		R[now].erase(it);
	}
	while (e[now] - dg[now] < L[now].size() && L[now].size()) {
		assert(L[now].size());
		auto it = --L[now].end(); Sum[now] -= *it;
		//cout << "unput : " << now << ' ' << *it << '\n';
		R[now].emplace(*it);
		L[now].erase(it);
	}
	ll& ret = dp[now][0] = Sum[now];

	for (auto& p : adj[now]) {
		ll nx = p.first, w = p.second;
		if (vis[nx]) continue;
		dfs(nx, k);
		ret += dp[nx][1];
		ll t = min(dp[nx][0] + w - dp[nx][1], 0LL);
		C[now].emplace(t);
	}

	
	//cout << "node is : " << now << ' ' << e[now] << ' ' << Sum[now] << '\n';
	
	// dp[now][0]
	auto it = R[now].begin();
	for (int i = 0; i < dg[now] && it != R[now].end(); i++) C[now].emplace(*it++);
	it = C[now].begin();
	/*for (ll x : L[now]) cout << x << ' ';
	cout << '\n';
	for (ll x : R[now]) cout << x << ' ';
	cout << '\n';
	for (ll x : C[now]) cout << x << ' ';
	cout << '\n';*/

	for(int i= 0; i < dg[now]; i++) /*assert(it != C[now].end()),*/ret += *it++;
	//cout << "ans + " << ret << "\n\n";

	// dp[now][1]
	ll p;
	//assert(C[now].size() || R[now].size());
	if (C[now].size()) p = *C[now].begin();
	else p = *R[now].begin();
	dp[now][1] = ret + p;

	C[now].clear();
	e[now]--;
	return;
}

vector<ll> minimum_closure_costs(int N, vector<int> U, vector<int> V, vector<int> W) {
	vector<ll> ans(N, 0);
	for (int i = 0; i < N - 1; i++) {
		adj[U[i]].emplace(V[i], W[i]);
		adj[V[i]].emplace(U[i], W[i]);
		dg[U[i]]++; dg[V[i]]++;
		ans[0] += W[i];
	}
	for (int i = 0; i < N; i++) {
		D[dg[i]].emplace_back(i); e[i] = dg[i] - 1;
		X.emplace(i);
	}

	for (int k = 1; k < N; k++) {
		// 노드 삭제하기
		//cout << "NOW TURN IS : " << k << '\n';
		for (int x : D[k]) {
			X.erase(x);
			//cout << "erase : " << x << '\n';
			for (auto& p : adj[x]) {
				ll nx = p.first, w = p.second;
				adj[nx].erase({ x, w }); dg[nx]--;
				R[nx].emplace(w);
				if (L[nx].size()) {
					auto l = --L[nx].end();
					auto r = R[nx].begin();
					ll lv = *l, rv = *r;
					if (lv > rv) {
						L[nx].erase(l); L[nx].emplace(rv);
						R[nx].erase(r); R[nx].emplace(lv);
					}
				}
			}
		}

		// 각 트리에 대해서 탐색
		for (int x : X) if (!vis[x]) {
			dfs(x, k);
			ans[k] += dp[x][0];
			//cout << "ans :  " << dp[x][0] << '\n';
		}
		for (int x : X) vis[x] = 0;
	}
	return ans;
}


//int main(void) {
//	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//
//	freopen("input.txt", "r", stdin);
//	int N;
//	cin >> N;
//	vector<int> U(N), V(N), W(N);
//	for (int i = 0; i < N - 1; i++) cin >> U[i] >> V[i] >> W[i];
//	vector<ll> ans = minimum_closure_costs(N, U, V, W);
//	for (int i = 0; i < N; i++) cout << ans[i] << ' ';
//	return 0;
//}

Compilation message (stderr)

roads.cpp: In function 'void dfs(int, int)':
roads.cpp:33:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  while (e[now] - dg[now] > L[now].size() && R[now].size()) {
      |         ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
roads.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |  while (e[now] - dg[now] < L[now].size() && L[now].size()) {
      |         ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 14
• Subtask 4: 0 / 10
• Subtask 5: 0 / 17
• Subtask 6: 0 / 25
• Subtask 7: 0 / 22