Submission #744535

#	Time	Username	Problem	Language	Result	Execution time	Memory
744535		RushB	Road Closures (APIO21_roads)	C++17	24 / 100	275 ms	5204 KiB

roads

#include "roads.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 2000 + 2;
long long dp[N][2];
int X;
vector<array<int, 2>> adj[N];

void dfs(int v, int p) {
	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());
	for (int i = 0; i <= X && i <= V.size(); i++) {
		if (i) ans += V[i - 1];
		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) {
	assert(n < N);
	long long all = 0;
	for (int i = 0; i < U.size(); i++) {
		adj[U[i]].push_back({V[i], W[i]});
		adj[V[i]].push_back({U[i], W[i]});
		all += W[i];
	}
	vector<long long> re(n);
	re[0] = all;
	for (int i = 1; i < n; i++) X = i, dfs(0, 0), re[i] = all - dp[0][0];
	return re;
}

Compilation message (stderr)

roads.cpp: In function 'void dfs(int, int)':
roads.cpp:21:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for (int i = 0; i <= X && i <= V.size(); i++) {
      |                            ~~^~~~~~~~~~~
roads.cpp:26:19: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   26 |  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:33:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  for (int i = 0; i < U.size(); i++) {
      |                  ~~^~~~~~~~~~

• Subtask 1: 0 / 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