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Submission #912762

# Submission time Handle Problem Language Result Execution time Memory
912762 2024-01-19T21:19:56 Z NK_ The Xana coup (BOI21_xanadu) C++17
100 / 100
 123 ms 37996 KB 
// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'
#define pb push_back
#define sz(x) int(x.size())

using ll = long long;
template<class T> using V = vector<T>;
using vi = V<int>;
using vl = V<ll>;

const int INF = 1e9 + 10;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N; cin >> N;

	V<vi> adj(N); for(int i = 0; i < N - 1; i++) {
		int u, v; cin >> u >> v; --u, --v;
		adj[u].pb(v);
		adj[v].pb(u);
	}	

	vi on(N); for(auto& x : on) cin >> x;

	V<V<vl>> dp(N, V<vl>(2, vl(2, INF)));

	function<void(int, int)> dfs = [&](int u, int p) {
		int amt = 0;
		for(auto& v : adj[u]) if (v != p) { dfs(v, u); amt++; }

		if (amt == 0) {
			// cout << u << " => " << on[u] << endl;
			dp[u][on[u]][0] = 0;
			dp[u][on[u] ^ 1][1] = 1;
		} else {
			for(int f = 0; f < 2; f++) {
				ll took = 0, flip = 0; vi chd;
				for(auto& v : adj[u]) if (v != p) {
					took += dp[v][f][1]; flip ^= 1;
					chd.pb(dp[v][f][0] - dp[v][f][1]);
				}

				sort(begin(chd), end(chd));

				dp[u][on[u] ^ f ^ flip][f] = min(dp[u][on[u] ^ f ^ flip][f], took + f);
				for(int i = 0; i < sz(chd); i++) {
					took += chd[i]; flip ^= 1;
					dp[u][on[u] ^ f ^ flip][f] = min(dp[u][on[u] ^ f ^ flip][f], took + f);
				}
			}
		}

		// cout << u << endl;
		// for(int v = 0; v < 2; v++) for(int f = 0; f < 2; f++) {
		// 	cout << v << " " << f << " ====> " << dp[u][v][f] << endl;
		// }

	};

	dfs(0, -1);

	int ans = min(dp[0][0][0], dp[0][0][1]);
	if (ans == INF) cout << "impossible" << nl;
	else cout << ans << nl;

	exit(0-0);
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 456 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 348 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 456 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 1 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 1 ms 344 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 344 KB Output is correct
16 Correct 0 ms 464 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 81 ms 36420 KB Output is correct
2 Correct 67 ms 36172 KB Output is correct
3 Correct 81 ms 36688 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 36576 KB Output is correct
2 Correct 68 ms 36168 KB Output is correct
3 Correct 72 ms 36688 KB Output is correct
4 Correct 64 ms 18772 KB Output is correct
5 Correct 99 ms 21872 KB Output is correct
6 Correct 77 ms 22540 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 19 ms 7772 KB Output is correct
9 Correct 86 ms 22144 KB Output is correct
10 Correct 88 ms 22728 KB Output is correct
11 Correct 80 ms 23188 KB Output is correct
12 Correct 87 ms 23968 KB Output is correct
13 Correct 70 ms 21076 KB Output is correct
14 Correct 80 ms 22544 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 1 ms 456 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 1 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 1 ms 344 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 344 KB Output is correct
16 Correct 0 ms 464 KB Output is correct
17 Correct 81 ms 36420 KB Output is correct
18 Correct 67 ms 36172 KB Output is correct
19 Correct 81 ms 36688 KB Output is correct
20 Correct 60 ms 36576 KB Output is correct
21 Correct 68 ms 36168 KB Output is correct
22 Correct 72 ms 36688 KB Output is correct
23 Correct 64 ms 18772 KB Output is correct
24 Correct 99 ms 21872 KB Output is correct
25 Correct 77 ms 22540 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 19 ms 7772 KB Output is correct
28 Correct 86 ms 22144 KB Output is correct
29 Correct 88 ms 22728 KB Output is correct
30 Correct 80 ms 23188 KB Output is correct
31 Correct 87 ms 23968 KB Output is correct
32 Correct 70 ms 21076 KB Output is correct
33 Correct 80 ms 22544 KB Output is correct
34 Correct 1 ms 348 KB Output is correct
35 Correct 0 ms 348 KB Output is correct
36 Correct 0 ms 348 KB Output is correct
37 Correct 0 ms 348 KB Output is correct
38 Correct 0 ms 348 KB Output is correct
39 Correct 1 ms 464 KB Output is correct
40 Correct 1 ms 344 KB Output is correct
41 Correct 1 ms 348 KB Output is correct
42 Correct 1 ms 348 KB Output is correct
43 Correct 1 ms 348 KB Output is correct
44 Correct 0 ms 348 KB Output is correct
45 Correct 64 ms 37996 KB Output is correct
46 Correct 64 ms 37460 KB Output is correct
47 Correct 63 ms 37972 KB Output is correct
48 Correct 75 ms 20444 KB Output is correct
49 Correct 77 ms 21876 KB Output is correct
50 Correct 75 ms 22540 KB Output is correct
51 Correct 1 ms 348 KB Output is correct
52 Correct 18 ms 7772 KB Output is correct
53 Correct 85 ms 22148 KB Output is correct
54 Correct 93 ms 22708 KB Output is correct
55 Correct 83 ms 23248 KB Output is correct
56 Correct 87 ms 23892 KB Output is correct
57 Correct 72 ms 21052 KB Output is correct
58 Correct 76 ms 22788 KB Output is correct
59 Correct 19 ms 7768 KB Output is correct
60 Correct 72 ms 20276 KB Output is correct
61 Correct 76 ms 21972 KB Output is correct
62 Correct 83 ms 22588 KB Output is correct
63 Correct 123 ms 22600 KB Output is correct
64 Correct 89 ms 22608 KB Output is correct
65 Correct 62 ms 23088 KB Output is correct
66 Correct 63 ms 23032 KB Output is correct
67 Correct 72 ms 23724 KB Output is correct
68 Correct 79 ms 23744 KB Output is correct
69 Correct 70 ms 23800 KB Output is correct
70 Correct 66 ms 23660 KB Output is correct