oj.uz

Submission #1081797

# Submission time Handle Problem Language Result Execution time Memory
1081797 2024-08-30T11:03:08 Z vuavisao Chase (CEOI17_chase) C++14
70 / 100
 335 ms 408656 KB 
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

using ll = long long;

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];
	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;
	}
}

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

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

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

	void dfsInOut(int u, int p) {
		// out is u can accept len >= 1
		for (int use = 0; use <= breads; ++ use) {
			dpOut[u][use][0] = (use == 0 ? make_pair(0ll, u) : make_pair(getCost(u, 0), u));
		}
		// in is u can accept len >= 2
		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);

			// case out:
			// prefix u = v
			for (int use = 0; use <= breads; ++ use) {
				pair<ll, int> cur = make_pair(dpOut[v][use][0].first, v);
				update(dpOut[u][use], cur);
				if (use < breads) {
					cur.first += getCost(u, v);
					update(dpOut[u][use + 1], cur);
				}
			}

			// case in:
			// prefix v = u
			for (int use = 0; use <= breads; ++ use) {
				auto 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);
		}
	}

	void solve() {
		for (int u = 1; u <= n; ++ u) {
			for (const auto& v : g[u]) {
				cost[v] += pigeons[u];
			}
		}
		dfsInOut(1, 0);
		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);
	sub4::solve();
	return (0 ^ 0);
}

/// Code by vuavisao

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2652 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 2652 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 4 ms 6704 KB Output is correct
8 Correct 3 ms 6748 KB Output is correct
9 Correct 3 ms 6744 KB Output is correct
10 Correct 5 ms 6748 KB Output is correct
11 Correct 3 ms 6748 KB Output is correct
12 Correct 3 ms 6748 KB Output is correct

Subtask #3
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 311 ms 408580 KB Output is correct
2 Correct 298 ms 408656 KB Output is correct
3 Correct 246 ms 402632 KB Output is correct
4 Correct 187 ms 402256 KB Output is correct
5 Correct 335 ms 402512 KB Output is correct
6 Correct 323 ms 402512 KB Output is correct
7 Correct 324 ms 402372 KB Output is correct

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2652 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 4 ms 6704 KB Output is correct
8 Correct 3 ms 6748 KB Output is correct
9 Correct 3 ms 6744 KB Output is correct
10 Correct 5 ms 6748 KB Output is correct
11 Correct 3 ms 6748 KB Output is correct
12 Correct 3 ms 6748 KB Output is correct
13 Correct 311 ms 408580 KB Output is correct
14 Correct 298 ms 408656 KB Output is correct
15 Correct 246 ms 402632 KB Output is correct
16 Correct 187 ms 402256 KB Output is correct
17 Correct 335 ms 402512 KB Output is correct
18 Correct 323 ms 402512 KB Output is correct
19 Correct 324 ms 402372 KB Output is correct
20 Correct 325 ms 402460 KB Output is correct
21 Correct 176 ms 402424 KB Output is correct
22 Incorrect 323 ms 402348 KB Output isn't correct
23 Halted 0 ms 0 KB -