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답안 #1088953

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1088953 2024-09-15T15:57:59 Z SamNguyen Museum (CEOI17_museum) C++14
100 / 100
 550 ms 784720 KB 
#include <bits/stdc++.h>
using namespace std;

#define INPFILE ".inp"
#define OUTFILE ".out"

const int INF = 3e8 + 7;

template <class T1, class T2>
inline bool minimise(T1 &x, T2 y) {
	if (x > y) { x = y; return true; }
	return false;
}

template <class T>
inline void minimise_pair(pair<T, T> &x, T y) {
	if (x.second > y)
		swap(x.second, y);
	if (x.first > x.second)
		swap(x.second, x.first);
}

const int MAX = 1e4 + 3;
int N, K, ROOT;
vector<pair<int, int>> adj[MAX];

void input() {
	cin >> N >> K >> ROOT;
	for (int t = N - 1; t--; ) {
		int u, v, w; cin >> u >> v >> w;
		adj[u].emplace_back(v, w);
		adj[v].emplace_back(u, w);
	}
}

int dp[2][MAX][MAX], sz[MAX];

void dfs(int u, int p) {
	sz[u] = 1;
	for (const auto &e : adj[u]) {
		int v, w;
		tie(v, w) = e;
		if (v == p) continue;
		dfs(v, u);
		sz[u] += sz[v];
	}

	static int g[MAX][2];

	g[0][true ] = 0;
	g[0][false] = 0;
	for (int s = min(K, sz[u]); s >= 1; s--) 
		g[s][true ] = g[s][false] = INF;

	int cum_size = 1;

	for (const auto &e : adj[u]) {
		int v, w;
		tie(v, w) = e;
		if (v == p) continue;

		for (int s = min(K, cum_size + sz[v]); s >= 1; s--) {
			for (int y = min(s, sz[v] + 1); y >= 1; y--) {
				int x = s - y;
				minimise(g[s][true ], g[x][true ] + 2 * w + dp[true ][v][y - 1]);
				minimise(g[s][false], g[x][false] + 2 * w + dp[true ][v][y - 1]);
				minimise(g[s][false], g[x][true ] +     w + dp[false][v][y - 1]);

				if (x > cum_size)
					break;
			}
		}
		cum_size += sz[v];

	}

	dp[true ][u][0] = 0;
	dp[false][u][0] = 0;
	for (int k = 1; k <= min(K, sz[u]); k++) {
		minimise(dp[false][u][k], g[k][false]);
		minimise(dp[true ][u][k], g[k][true ]);
	}
}

void solve() {
	if (K == 1) {
		cout << 0;
		return;
	}

	for (int t : {0, 1})
	for (int u = 0; u <= N; u++)
	for (int k = 0; k <= K; k++)
		dp[t][u][k] = INF;
	
	adj[0].emplace_back(ROOT, 0);
	dfs(0, -1);

	int ans = dp[false][0][K];
	cout << ans;
}
	
int main(void) {
	if (fopen(INPFILE, "r")) {
		freopen(INPFILE, "r", stdin);
		freopen(OUTFILE, "w", stdout);
	}
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);

	input();
	solve();

	return 0;
}

Compilation message

museum.cpp: In function 'int main()':
museum.cpp:105:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |   freopen(INPFILE, "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
museum.cpp:106:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |   freopen(OUTFILE, "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 860 KB Output is correct
2 Correct 1 ms 860 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 0 ms 860 KB Output is correct
5 Correct 0 ms 860 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 90464 KB Output is correct
2 Correct 46 ms 90452 KB Output is correct
3 Correct 48 ms 90704 KB Output is correct
4 Correct 57 ms 90484 KB Output is correct
5 Correct 42 ms 90520 KB Output is correct

Subtask #3
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 90464 KB Output is correct
2 Correct 46 ms 90452 KB Output is correct
3 Correct 48 ms 90704 KB Output is correct
4 Correct 57 ms 90484 KB Output is correct
5 Correct 42 ms 90520 KB Output is correct
6 Correct 39 ms 90452 KB Output is correct
7 Correct 41 ms 90708 KB Output is correct
8 Correct 39 ms 90448 KB Output is correct
9 Correct 39 ms 90460 KB Output is correct
10 Correct 38 ms 90608 KB Output is correct

Subtask #4
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 860 KB Output is correct
2 Correct 1 ms 860 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 0 ms 860 KB Output is correct
5 Correct 0 ms 860 KB Output is correct
6 Correct 44 ms 90464 KB Output is correct
7 Correct 46 ms 90452 KB Output is correct
8 Correct 48 ms 90704 KB Output is correct
9 Correct 57 ms 90484 KB Output is correct
10 Correct 42 ms 90520 KB Output is correct
11 Correct 39 ms 90452 KB Output is correct
12 Correct 41 ms 90708 KB Output is correct
13 Correct 39 ms 90448 KB Output is correct
14 Correct 39 ms 90460 KB Output is correct
15 Correct 38 ms 90608 KB Output is correct
16 Correct 84 ms 160764 KB Output is correct
17 Correct 245 ms 473428 KB Output is correct
18 Correct 93 ms 160988 KB Output is correct
19 Correct 103 ms 160848 KB Output is correct
20 Correct 91 ms 160848 KB Output is correct
21 Correct 492 ms 784468 KB Output is correct
22 Correct 418 ms 784584 KB Output is correct
23 Correct 524 ms 784328 KB Output is correct
24 Correct 388 ms 784464 KB Output is correct
25 Correct 550 ms 784720 KB Output is correct