Submission #744581

#	Time	Username	Problem	Language	Result	Execution time	Memory
744581		RushB	Road Closures (APIO21_roads)	C++17	31 / 100	2083 ms	62656 KiB

roads

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

struct segment_tree {
	vector<int> sum, cnt;
	int n = 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 -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;
	}
	void add(int id, int x, int l, int r, int v = 1) {
		if (l + 1 == r) {
			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]) return void(dp[v][0] = dp[v][1] = 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];
		if (w + dp[u][1] > 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] = SEG[v].get(X - i) + ans
		//dp[v][1] = SEG[v].get(X - i - 1) + ans
		mx = max(mx, ans);
		if (i + 1 == X) dp[v][1] = mx + dif;
	}
	if (V.size() + 1 < X) dp[v][1] = mx + dif;
	dp[v][0] = mx + dif;
}

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]});
		val[U[i]].push_back(W[i]);
		val[V[i]].push_back(W[i]);
		all += W[i];
	}
	for (int i = 0; i < n; i++) sort(val[i].begin(), val[i].end()), SEG[i].init(val[i].size());

	iota(p, p + n, 0), sort(p, p + n, [&](const int x, const int y) {return adj[x].size() < adj[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++) {
		X = i; 
		for (;ptr < n && adj[p[ptr]].size() <= i; ptr++) {
			int v = p[ptr];
			array<int, 2> P;
			for (auto it = adj[v].begin(); it != adj[v].end(); it = adj[v].upper_bound(P)) {
				P = *it;
				if (enb[P[0]]) {
					all -= P[1];
					adj[v].erase(it);
					adj[P[0]].erase({v, P[1]});
					SEG[v].add(lower_bound(val[v].begin(), val[v].end(), P[1]) - val[v].begin(), P[1], 0, val[v].size(), 1); //at loc P[1] and v
				}
			}
			enb[v] = true;
			S.erase(v);
		}
		long long ans = 0;
		for (auto v: S) if (!mark[v]) {
			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:25:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |    int m = l + r >> 1;
      |            ~~^~~
roads.cpp: In member function 'void segment_tree::add(int, int, int, int, int)':
roads.cpp:38:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   38 |   int m = l + r >> 1;
      |           ~~^~~
roads.cpp: In function 'void dfs(int, int)':
roads.cpp:65:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |  for (int i = 0; i <= X && i <= V.size(); i++) {
      |                            ~~^~~~~~~~~~~
roads.cpp:72:19: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   72 |  if (V.size() + 1 < X) dp[v][1] = mx + dif;
      |      ~~~~~~~~~~~~~^~~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:78:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |  for (int i = 0; i < U.size(); i++) {
      |                  ~~^~~~~~~~~~
roads.cpp:94:39: warning: comparison of integer expressions of different signedness: 'std::set<std::array<int, 2> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   94 |   for (;ptr < n && adj[p[ptr]].size() <= i; ptr++) {
      |                    ~~~~~~~~~~~~~~~~~~~^~~~

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