Submission #744614

#	Time	Username	Problem	Language	Result	Execution time	Memory
744614		RushB	Road Closures (APIO21_roads)	C++17	49 / 100	401 ms	73000 KiB

roads

#include "roads.h"
#include <bits/stdc++.h>
//PAIN ^ 2
using namespace std;
const int N = 1e5 + 5;
const long long INF = 1ll << 60;
long long dp[N][2];
int X, p[N], deg[N];
set<array<int, 2>> adj[N];
vector<array<int, 2>> adjV[N];
vector<int> rec;
set<int> S;
bitset<N> enb, mark;

struct segment_tree {
	vector<long long> sum, cnt;
	int n = 0, kol = 0;
	void init(int _n) {
		n = _n;
		sum.assign(4 * n, 0);
		cnt.assign(4 * n, 0);
	}
	long long get(int x) {
		if (x <= 0) return (x == 0 ? 0 : -INF);
		int l = 0, r = n, v = 1, s = 0;
		while (r - l > 1) {
			int m = l + r >> 1;
			v <<= 1;
			if (cnt[v] >= x) r = m;
			else x -= cnt[v], s += sum[v], v |= 1, l = m;
		}
		return s + sum[v];
	}
	void add(int id, int x, int l, int r, int v = 1) {
		if (l + 1 == r) {
			kol += x;
			sum[v] += x;
			cnt[v]++;
			return;
		}
		int m = l + r >> 1;
		if (id < m) add(id, x, l, m, v << 1);
		else add(id, x, m, r, v << 1 | 1);
		sum[v] = sum[v << 1] + sum[v << 1 | 1];
		cnt[v] = cnt[v << 1] + cnt[v << 1 | 1];
	}
} SEG[N];

void dfs(int v, int p) {
	if (enb[v]) assert(0);

	rec.push_back(v);
	mark[v] = true;

	long long dif = 0, ans = 0, mx = 0;
	vector<long long> V;
	V.reserve(adj[v].size());

	for (auto P: adj[v]) {
		int u = P[0], w = P[1];
		if (u == p) continue;
		dfs(u, v);
		dif += dp[u][0];
		V.push_back(w + dp[u][1] - dp[u][0]);
	}
	sort(V.rbegin(), V.rend());
	dp[v][0] = dp[v][1] = 0;
	for (int i = 0; i <= X && i <= V.size(); i++) {
		if (i) ans += V[i - 1];
		dp[v][0] = max(dp[v][0], SEG[v].get(X - i) + ans + dif);
		dp[v][1] = max(dp[v][1], SEG[v].get(X - i - 1) + ans + dif);
		//if (v == 0)
			//cout << "i: " << i << " (chosen from V) that is " << ans << " SEG: " << SEG[v].get(X - i) << endl;
	}
	//cout << "V: " << v << " SEG: " << SEG[v].kol << " dp[0] " << dp[v][0] << " dp[1] " << dp[v][1] << endl;
}

vector<long long> minimum_closure_costs(int n, vector<int> U, vector<int> V, vector<int> W) {
	long long all = 0;
	for (int i = 0; i < U.size(); i++) {
		adj[U[i]].insert({V[i], W[i]});
		adj[V[i]].insert({U[i], W[i]});
		adjV[U[i]].push_back({-W[i], V[i]});
		adjV[V[i]].push_back({-W[i], U[i]});
		all += W[i];
	}
	for (int i = 0; i < n; i++) sort(adjV[i].begin(), adjV[i].end()), SEG[i].init(adjV[i].size());

	iota(p, p + n, 0), sort(p, p + n, [&](const int x, const int y) {return adjV[x].size() < adjV[y].size();});
	for (int i = 0; i < n; i++) S.insert(i);

	vector<long long> re(n);
	re[0] = all;
	for (int i = 1, ptr = 0; i < n; i++) { //TODO
		X = i; 
		for (;ptr < n && adjV[p[ptr]].size() <= i; ptr++) {
			int v = p[ptr];
			array<int, 2> P;
			for (auto P: adjV[v]) {
				int u = P[1], w = -P[0];
				if (enb[u]) all -= w;
				else {
					SEG[u].add(lower_bound(adjV[u].begin(), adjV[u].end(), array<int, 2>{-w, v}) - adjV[u].begin(), w, 0, adjV[u].size(), 1); //at loc P[1] and v
					//cout << "ADDING TO " << u << " edge: " << w << endl;
				}
				adj[v].erase(P);
				adj[u].erase({v, w});
			}
			enb[v] = true;
			S.erase(v);
		}
		long long ans = 0;
		for (auto v: S) if (!mark[v]) {
			//cout << "DFS: " << v << endl;
			dfs(v, v);
			ans += dp[v][0];
		}

		for (auto v: rec) mark[v] = 0;
		rec.clear();

		re[i] = all - ans;
	}
	return re;
}

Compilation message (stderr)

roads.cpp: In member function 'long long int segment_tree::get(int)':
roads.cpp:27:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   27 |    int m = l + r >> 1;
      |            ~~^~~
roads.cpp: In member function 'void segment_tree::add(int, int, int, int, int)':
roads.cpp:41:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   41 |   int m = l + r >> 1;
      |           ~~^~~
roads.cpp: In function 'void dfs(int, int)':
roads.cpp:68:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |  for (int i = 0; i <= X && i <= V.size(); i++) {
      |                            ~~^~~~~~~~~~~
roads.cpp:55:30: warning: unused variable 'mx' [-Wunused-variable]
   55 |  long long dif = 0, ans = 0, mx = 0;
      |                              ^~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:80:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |  for (int i = 0; i < U.size(); i++) {
      |                  ~~^~~~~~~~~~
roads.cpp:96:40: warning: comparison of integer expressions of different signedness: 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   96 |   for (;ptr < n && adjV[p[ptr]].size() <= i; ptr++) {
      |                    ~~~~~~~~~~~~~~~~~~~~^~~~
roads.cpp:98:18: warning: unused variable 'P' [-Wunused-variable]
   98 |    array<int, 2> P;
      |                  ^

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