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Submission #1081819

# Submission time Handle Problem Language Result Execution time Memory
1081819 2024-08-30T11:34:17 Z vuavisao Chase (CEOI17_chase) C++14
100 / 100
 315 ms 407888 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 100'000 + 1;

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

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

	int parent[N];
	long long curPigeons[N];

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

	long long dfs(int u, long long cur, int use) {
		long long res = 0;

		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));
		}

		if (use < breads) {
			vector<long long> 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() {
		long long 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);
	}

	long long dp[N][110];

	void dfs(int u, int p) {
		long long 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);
		}
	}

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

namespace sub4 {
	pair<long long, int> dpOut[N][101][2];
	long long dpIn[N][101];
	long long cost[N];
	long long res = 0;

	long long getCost(int u, int p) {
		return cost[u] - pigeons[p];
	}

	void update(pair<long long, int> cur[], pair<long long, int> val) {
		pair<long long, int> old = cur[0];
		if (val.first > cur[0].first) {
			cur[0] = val;
			cur[1] = old;
		}
		else {
			cur[1] = max(cur[1], val);
		}
	}

	void dfsInOut(int u, int p) {
		for (int use = 0; use <= breads; ++ use) {
			dpOut[u][use][0] = (use == 0 ? make_pair(0ll, u) : make_pair(getCost(u, 0), u));
		}
		for (int use = 0; use <= breads; ++ use) {
			dpIn[u][use] = (use == 0 ? 0ll : getCost(u, p));
		}

		for (const auto& v : g[u]) {
			if (v == p) continue;
			dfsInOut(v, u);

			for (int use = 0; use <= breads; ++ use) {
				pair<long long, int> cur = make_pair(dpOut[v][use][0].first, v);
				if (use > 0) {
					cur.first = max(cur.first, dpOut[v][use - 1][0].first + getCost(u, v));
				}
				update(dpOut[u][use], cur);
			}

			for (int use = 0; use <= breads; ++ use) {
				long long cur = dpIn[v][use];
				dpIn[u][use] = max(dpIn[u][use], cur);
				if (use < breads) {
					cur += getCost(u, p);
					dpIn[u][use + 1] = max(dpIn[u][use + 1], cur);
				}
			}
		}

		for (const auto& v : g[u]) {
			if (v == p) continue;
			
			for (int useOut = 0; useOut <= breads; ++ useOut) {
				int useIn = breads - useOut;
				for (int typeOut = 0; typeOut < 2; ++ typeOut) {
					if (dpOut[u][useOut][typeOut].second == v) continue;
					res = max(res, dpOut[u][useOut][typeOut].first + dpIn[v][useIn]);
				}
			}
		}
		for (int useOut = 0; useOut <= breads; ++ useOut) {
			res = max(res, dpOut[u][useOut][0].first);
		}
		for (int useIn = 0; useIn <= breads; ++ useIn) {
			res = max(res, dpIn[u][useIn]);
		}
	}

	void solve() {
		for (int u = 1; u <= n; ++ u) {
			for (const auto& v : g[u]) {
				cost[v] += pigeons[u];
			}
		}
		dfsInOut(1, 0);
		cout << res;
	}

}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr); 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);
	sub4::solve();
	return 0;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2904 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 2652 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

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2904 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 2652 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 276 ms 3676 KB Output is correct
8 Correct 27 ms 3676 KB Output is correct
9 Correct 24 ms 3676 KB Output is correct
10 Correct 291 ms 3700 KB Output is correct
11 Correct 110 ms 3676 KB Output is correct
12 Correct 37 ms 3672 KB Output is correct

Subtask #3
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 294 ms 407888 KB Output is correct
2 Correct 285 ms 407636 KB Output is correct
3 Correct 257 ms 402780 KB Output is correct
4 Correct 177 ms 402292 KB Output is correct
5 Correct 296 ms 402256 KB Output is correct
6 Correct 308 ms 402516 KB Output is correct
7 Correct 312 ms 402512 KB Output is correct

Subtask #4
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2904 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 2652 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 276 ms 3676 KB Output is correct
8 Correct 27 ms 3676 KB Output is correct
9 Correct 24 ms 3676 KB Output is correct
10 Correct 291 ms 3700 KB Output is correct
11 Correct 110 ms 3676 KB Output is correct
12 Correct 37 ms 3672 KB Output is correct
13 Correct 294 ms 407888 KB Output is correct
14 Correct 285 ms 407636 KB Output is correct
15 Correct 257 ms 402780 KB Output is correct
16 Correct 177 ms 402292 KB Output is correct
17 Correct 296 ms 402256 KB Output is correct
18 Correct 308 ms 402516 KB Output is correct
19 Correct 312 ms 402512 KB Output is correct
20 Correct 310 ms 402304 KB Output is correct
21 Correct 170 ms 402512 KB Output is correct
22 Correct 298 ms 402512 KB Output is correct
23 Correct 176 ms 402256 KB Output is correct
24 Correct 315 ms 402416 KB Output is correct
25 Correct 250 ms 402664 KB Output is correct
26 Correct 291 ms 407888 KB Output is correct
27 Correct 306 ms 407868 KB Output is correct