Submission #677682

#	Time	Username	Problem	Language	Result	Execution time	Memory
677682		YENGOYAN	Road Closures (APIO21_roads)	C++17	29 / 100	421 ms	32140 KiB

roads

#include "roads.h"
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_map>
#include <cmath>
#include <climits>
#include <algorithm>
#include <random>
#include <queue>
#include <deque>
#include <iomanip>
#include <string>
#include <tuple>
#include <bitset>
#include <chrono>
#include <ctime>
#include <fstream>
#include <stack>
#include <cstdio>
using namespace std;
using ll = long long;

vector<vector<pair<int, int>>> gp;
vector<vector<ll>> dp;
vector<ll> linear_w;

void dfs(int u, int p, int k) {
	vector<ll> vec;
	dp[u][0] = 0;
	for (pair<int, int>& v : gp[u]) {
		if (v.first == p) continue;
		dfs(v.first, u, k);
		dp[u][0] += dp[v.first][k];
		vec.push_back(dp[v.first][k - 1] + v.second - dp[v.first][k]);
	}
	sort(vec.rbegin(), vec.rend());
	int lsti = 0;
	for (int i = 1, j = 0; i <= k && j < vec.size(); ++i, ++j) {
		dp[u][i] = dp[u][i - 1];
		dp[u][i] += max(0ll, vec[j]);
		lsti = i;
	}
	if (lsti < k) dp[u][k] = dp[u][lsti];
	if (lsti < k - 1) dp[u][k - 1] = dp[u][lsti];
}

void to_line(int u, int p) {
	for (pair<int, int>& v : gp[u]) {
		if (v.first == p) continue;
		linear_w.push_back(v.second);
		to_line(v.first, u);
	}
}

vector<ll> minimum_closure_costs(int n, vector<int> U, vector<int> V, vector<int> W) {
	gp = vector<vector<pair<int, int>>>(n);
	ll sm = 0;
	bool f = 1;
	for (int i = 0; i < U.size(); ++i) {
		gp[U[i]].push_back({ V[i], W[i] });
		gp[V[i]].push_back({ U[i], W[i] });
		if (U[i]) f = 0;
		sm += W[i];
	}
	vector<ll> vec(n);
	if (f) {
		sort(W.rbegin(), W.rend());
		ll cur = 0;
		for (int i = 0; i < n; ++i) {
			//cout << sm - cur << " ";
			vec[i] = sm - cur;
			if(i < n - 1) cur += W[i];
		}
		return vec;
	}
	if (n > 2000) {
		int node = 0;
		for (int i = 0; i < n; ++i) if (gp[i].size() == 1) node = i;
		to_line(node, node);
		vector<ll> DP(n - 1);
		DP[0] = linear_w[0];
		if (n > 2) DP[1] = max(DP[0], linear_w[1]);
		if (n > 3) DP[2] = max(DP[1], DP[0] + linear_w[2]);
		for(int i = 3; i < n - 1; ++i){
			DP[i] = max(DP[i - 1], DP[i - 2] + linear_w[i]);
		}
		vec[0] = sm;
		vec[1] = sm - DP[n - 2];
		dp = vector<vector<ll>>(n, vector<ll>(2));
		dp[0][0] = 0;
		dp[0][1] = linear_w[0];
		dp[1][0] = linear_w[1];
		dp[1][1] = dp[0][1] + dp[1][0];
		for (int i = 2; i < n - 1; ++i) {
			dp[i][0] = max(dp[i - 2][0], dp[i - 2][1]) + linear_w[i];
			dp[i][1] = max({ dp[i - 2][0], dp[i - 2][1] , dp[i - 1][0] }) + linear_w[i];
		}
		if (vec.size() > 2) vec[2] = sm - max(dp[n - 2][0], dp[n - 2][1]);
		for (int i = 3; i < n; ++i) vec[i] = vec[i - 1];
		return vec;
	}
	vec[0] = sm;
	dp = vector<vector<ll>>(n, vector<ll>(n));
	for (int i = 1; i < n; ++i) {
		dfs(0, 0, i);
		vec[i] = sm - dp[0][i];
	}
	return vec;
}

Compilation message (stderr)

roads.cpp: In function 'void dfs(int, int, int)':
roads.cpp:41:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |  for (int i = 1, j = 0; i <= k && j < vec.size(); ++i, ++j) {
      |                                   ~~^~~~~~~~~~~~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:62:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |  for (int i = 0; i < U.size(); ++i) {
      |                  ~~^~~~~~~~~~

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