oj.uz

답안 #1081522

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1081522 2024-08-30T06:59:05 Z vuavisao Chase (CEOI17_chase) C++14
70 / 100
 219 ms 97620 KB 
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

using ll = long long;

const int N = 100'000 + 10;

int n, breads;
int pigeons[N];
vector<int> g[N];

namespace sub1 {
	bool check() {
		return (n <= 10);
	}

	int parent[N];
	ll curPigeons[N];

	ll getDiff(int u, ll cur) {
		ll after = 0;
		while (u != 0) {
			after += curPigeons[u];
			u = parent[u];
		}
		return abs(after - cur);
	}

	ll dfs(int u, ll cur, int use) {
		ll res = 0;
		// doesn't drop the breadcrumb
		cur += curPigeons[u];
		res = max(res, getDiff(u, cur));
		for (const auto& v : g[u]) {
			if (v == parent[u]) continue;
			parent[v] = u;
			res = max(res, dfs(v, cur, use));
		}

		// drop the breadcrumb
		if (use < breads) {
			vector<ll> oldPigeons(n + 1, 0);
			oldPigeons[u] = curPigeons[u];
			for (const auto& v : g[u]) {
				oldPigeons[v] = curPigeons[v];
			}
			for (const auto& v : g[u]) {
				curPigeons[u] += curPigeons[v];
				curPigeons[v] = 0;
			}

			res = max(res, getDiff(u, cur));
			
			for (const auto& v : g[u]) {
				if (v == parent[u]) continue;
				parent[v] = u;
				res = max(res, dfs(v, cur, use + 1));
			}

			curPigeons[u] = oldPigeons[u];
			for (const auto& v : g[u]) {
				curPigeons[v] = oldPigeons[v];
			}
		}
		return res;
	}

	void solve() {
		ll res = 0;
		for (int root = 1; root <= n; ++ root) {
			for (int u = 1; u <= n; ++ u) {
				curPigeons[u] = pigeons[u];
				parent[u] = 0;
			}
			res = max(res, dfs(root, 0, 0));
		}
		cout << res;
	}
}

namespace sub2 {
	bool check() {
		return (n <= 1'000);
	}

	ll dp[N][110];

	void dfs(int u, int p) {
		ll bonus = -pigeons[p];
		for (const auto& v : g[u]) {
			bonus += pigeons[v];
		}
		for (int use = breads - 1; use >= 0; -- use) {
			dp[u][use + 1] = max(dp[u][use + 1], dp[u][use] + bonus);
		}
		for (const auto& v : g[u]) {
			if (v == p) continue;
			for (int use = 0; use <= breads; ++ use) {
				dp[v][use] = max(dp[v][use], dp[u][use]);
			}
			dfs(v, u);
		}
	}

	ll calc(int root) {
		for (int u = 0; u <= n + 1; ++ u) {
			for (int use = 0; use <= breads + 1; ++ use) {
				dp[u][use] = 0;
			}
		}
		dfs(root, 0);
		ll res = 0;
		for (int u = 1; u <= n; ++ u) {
			for (int use = 0; use <= breads; ++ use) {
				res = max(res, dp[u][use]);
			}
		}
		return res;
	}

	void solve() {
		ll res = 0;
		for (int root = 1; root <= n; ++ root) {
			res = max(res, calc(root));
		}
		cout << res;
	}
}

int32_t main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr); std::cout.tie(nullptr);
	cin >> n >> breads;
	for (int u = 1; u <= n; ++ u) cin >> pigeons[u];
	for (int i = 2; i <= n; ++ i) {
		int u, v; cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	if (sub1::check()) {
		sub1::solve();
		return 0;
	}
	if (sub2::check()) {
		sub2::solve();
		return 0;
	}
	cout << sub2::calc(1);
	return (0 ^ 0);
}

/// Code by vuavisao

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 217 ms 3676 KB Output is correct
8 Correct 29 ms 3672 KB Output is correct
9 Correct 21 ms 3732 KB Output is correct
10 Correct 219 ms 3712 KB Output is correct
11 Correct 91 ms 3672 KB Output is correct
12 Correct 35 ms 3672 KB Output is correct

Subtask #3
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 119 ms 97620 KB Output is correct
2 Correct 104 ms 97620 KB Output is correct
3 Correct 72 ms 94956 KB Output is correct
4 Correct 66 ms 94548 KB Output is correct
5 Correct 120 ms 94544 KB Output is correct
6 Correct 124 ms 94544 KB Output is correct
7 Correct 119 ms 94396 KB Output is correct

Subtask #4
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 217 ms 3676 KB Output is correct
8 Correct 29 ms 3672 KB Output is correct
9 Correct 21 ms 3732 KB Output is correct
10 Correct 219 ms 3712 KB Output is correct
11 Correct 91 ms 3672 KB Output is correct
12 Correct 35 ms 3672 KB Output is correct
13 Correct 119 ms 97620 KB Output is correct
14 Correct 104 ms 97620 KB Output is correct
15 Correct 72 ms 94956 KB Output is correct
16 Correct 66 ms 94548 KB Output is correct
17 Correct 120 ms 94544 KB Output is correct
18 Correct 124 ms 94544 KB Output is correct
19 Correct 119 ms 94396 KB Output is correct
20 Incorrect 118 ms 94440 KB Output isn't correct
21 Halted 0 ms 0 KB -