답안 #446675

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
446675	2021-07-23T06:11:05 Z	wind_reaper	The Xana coup (BOI21_xanadu)	C++17	100 / 100	77 ms	21616 KB

xanadu

#include <bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
*/

using namespace std;
// using namespace __gnu_pbds;
using namespace chrono;

// mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
/*
template <class T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
*/

//***************** CONSTANTS *****************

const int MXN = 100000;
const int INF = 0x3f3f3f3f;

//***************** GLOBAL VARIABLES *****************

int dp[MXN][2][2], on[MXN];
vector<int> g[MXN];

//***************** AUXILIARY STRUCTS *****************



//***************** MAIN BODY *****************

void dfs(int u, int p){
	int temp[2][2][2];
	memset(temp, INF, sizeof temp);

	temp[0][0][0] = temp[0][1][0] = 0;
	for(int v : g[u]) if(v != p){
		dfs(v, u);
		memset(temp[1], INF, sizeof temp[1]);

		for(int i = 0; i < 2; i++)
			for(int j = 0; j < 2; j++)
				for(int k = 0; k < 2; k++)
					temp[1][i][j^k] = min(temp[1][i][j^k], temp[0][i][j] + dp[v][i][k]);

		swap(temp[0], temp[1]);
	}

	dp[u][0][0] = temp[0][0][on[u]];
	dp[u][0][1] = temp[0][1][on[u]^1] + 1;
	dp[u][1][0] = temp[0][0][on[u]^1];
	dp[u][1][1] = temp[0][1][on[u]] + 1;
}

void solve(){
	int N;
	cin >> N;

	for(int i = 0; i < N - 1; i++){
		int u, v;
		cin >> u >> v;
		--u, --v;
		g[u].push_back(v);
		g[v].push_back(u);
	}

	for(int i = 0; i < N; i++)
		cin >> on[i];

	memset(dp, INF, sizeof dp);

	dfs(0, 0);

	int ans = min(dp[0][0][0], dp[0][0][1]);

	if(ans > N) cout << "impossible\n";
	else cout << ans << '\n';
}

/*
	dp[N][2][2] -> dp[u][i][j] -> currently considering the uth node in state i and press j
	temp[c][2][2] -> tmp[v][i][j] -> vth child, is u toggled, j -> parity of selection
*/

//***************** *****************

int32_t main(){
	ios_base::sync_with_stdio(NULL);
	cin.tie(NULL);

	#ifdef LOCAL
		auto begin = high_resolution_clock::now();
	#endif

	int tc = 1;
	// cin >> tc; 
	for (int t = 0; t < tc; t++)
		solve();

	#ifdef LOCAL 
		auto end = high_resolution_clock::now();
		cout << fixed << setprecision(4);
		cout << "Execution Time: " << duration_cast<duration<double>>(end - begin).count() << "seconds" << endl;
	#endif

	return 0;
}

/*
If code gives a WA, check for the following : 
1. I/O format

2. Are you clearing all global variables in between tests if multitests are a thing

3. Can you definitively prove the logic
*/

Subtask #1
5.0 / 5.0

#	결과	실행 시간	메모리	Grader output
1	Correct	3 ms	4172 KB	Output is correct
2	Correct	3 ms	4204 KB	Output is correct
3	Correct	3 ms	4172 KB	Output is correct
4	Correct	3 ms	4172 KB	Output is correct
5	Correct	3 ms	4204 KB	Output is correct

Subtask #2
15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	3 ms	4172 KB	Output is correct
2	Correct	3 ms	4204 KB	Output is correct
3	Correct	3 ms	4172 KB	Output is correct
4	Correct	3 ms	4172 KB	Output is correct
5	Correct	3 ms	4204 KB	Output is correct
6	Correct	3 ms	4172 KB	Output is correct
7	Correct	3 ms	4172 KB	Output is correct
8	Correct	3 ms	4172 KB	Output is correct
9	Correct	3 ms	4212 KB	Output is correct
10	Correct	3 ms	4172 KB	Output is correct
11	Correct	3 ms	4172 KB	Output is correct
12	Correct	3 ms	4172 KB	Output is correct
13	Correct	3 ms	4172 KB	Output is correct
14	Correct	3 ms	4172 KB	Output is correct
15	Correct	3 ms	4172 KB	Output is correct
16	Correct	3 ms	4172 KB	Output is correct

Subtask #3
10.0 / 10.0

#	결과	실행 시간	메모리	Grader output
1	Correct	69 ms	21472 KB	Output is correct
2	Correct	64 ms	21188 KB	Output is correct
3	Correct	69 ms	21600 KB	Output is correct

Subtask #4
40.0 / 40.0

#	결과	실행 시간	메모리	Grader output
1	Correct	64 ms	21424 KB	Output is correct
2	Correct	64 ms	21188 KB	Output is correct
3	Correct	67 ms	21544 KB	Output is correct
4	Correct	56 ms	8536 KB	Output is correct
5	Correct	64 ms	8984 KB	Output is correct
6	Correct	67 ms	9056 KB	Output is correct
7	Correct	3 ms	4172 KB	Output is correct
8	Correct	19 ms	5812 KB	Output is correct
9	Correct	64 ms	9124 KB	Output is correct
10	Correct	68 ms	9168 KB	Output is correct
11	Correct	69 ms	9992 KB	Output is correct
12	Correct	66 ms	10180 KB	Output is correct
13	Correct	62 ms	8776 KB	Output is correct
14	Correct	63 ms	9056 KB	Output is correct

Subtask #5
30.0 / 30.0

#	결과	실행 시간	메모리	Grader output
1	Correct	3 ms	4172 KB	Output is correct
2	Correct	3 ms	4204 KB	Output is correct
3	Correct	3 ms	4172 KB	Output is correct
4	Correct	3 ms	4172 KB	Output is correct
5	Correct	3 ms	4204 KB	Output is correct
6	Correct	3 ms	4172 KB	Output is correct
7	Correct	3 ms	4172 KB	Output is correct
8	Correct	3 ms	4172 KB	Output is correct
9	Correct	3 ms	4212 KB	Output is correct
10	Correct	3 ms	4172 KB	Output is correct
11	Correct	3 ms	4172 KB	Output is correct
12	Correct	3 ms	4172 KB	Output is correct
13	Correct	3 ms	4172 KB	Output is correct
14	Correct	3 ms	4172 KB	Output is correct
15	Correct	3 ms	4172 KB	Output is correct
16	Correct	3 ms	4172 KB	Output is correct
17	Correct	69 ms	21472 KB	Output is correct
18	Correct	64 ms	21188 KB	Output is correct
19	Correct	69 ms	21600 KB	Output is correct
20	Correct	64 ms	21424 KB	Output is correct
21	Correct	64 ms	21188 KB	Output is correct
22	Correct	67 ms	21544 KB	Output is correct
23	Correct	56 ms	8536 KB	Output is correct
24	Correct	64 ms	8984 KB	Output is correct
25	Correct	67 ms	9056 KB	Output is correct
26	Correct	3 ms	4172 KB	Output is correct
27	Correct	19 ms	5812 KB	Output is correct
28	Correct	64 ms	9124 KB	Output is correct
29	Correct	68 ms	9168 KB	Output is correct
30	Correct	69 ms	9992 KB	Output is correct
31	Correct	66 ms	10180 KB	Output is correct
32	Correct	62 ms	8776 KB	Output is correct
33	Correct	63 ms	9056 KB	Output is correct
34	Correct	3 ms	4172 KB	Output is correct
35	Correct	3 ms	4172 KB	Output is correct
36	Correct	3 ms	4204 KB	Output is correct
37	Correct	3 ms	4208 KB	Output is correct
38	Correct	3 ms	4204 KB	Output is correct
39	Correct	3 ms	4172 KB	Output is correct
40	Correct	3 ms	4172 KB	Output is correct
41	Correct	3 ms	4172 KB	Output is correct
42	Correct	3 ms	4208 KB	Output is correct
43	Correct	3 ms	4172 KB	Output is correct
44	Correct	3 ms	4172 KB	Output is correct
45	Correct	66 ms	21496 KB	Output is correct
46	Correct	66 ms	21216 KB	Output is correct
47	Correct	68 ms	21616 KB	Output is correct
48	Correct	65 ms	8516 KB	Output is correct
49	Correct	77 ms	8940 KB	Output is correct
50	Correct	64 ms	9052 KB	Output is correct
51	Correct	3 ms	4140 KB	Output is correct
52	Correct	21 ms	5836 KB	Output is correct
53	Correct	68 ms	9028 KB	Output is correct
54	Correct	65 ms	9168 KB	Output is correct
55	Correct	65 ms	9940 KB	Output is correct
56	Correct	68 ms	10156 KB	Output is correct
57	Correct	76 ms	8732 KB	Output is correct
58	Correct	75 ms	9016 KB	Output is correct
59	Correct	20 ms	5836 KB	Output is correct
60	Correct	58 ms	8660 KB	Output is correct
61	Correct	67 ms	9156 KB	Output is correct
62	Correct	65 ms	9176 KB	Output is correct
63	Correct	70 ms	9156 KB	Output is correct
64	Correct	64 ms	9180 KB	Output is correct
65	Correct	60 ms	9608 KB	Output is correct
66	Correct	60 ms	9540 KB	Output is correct
67	Correct	48 ms	9476 KB	Output is correct
68	Correct	52 ms	9588 KB	Output is correct
69	Correct	47 ms	9420 KB	Output is correct
70	Correct	47 ms	9456 KB	Output is correct

답안 #446675

Compilation message

Subtask #1 5.0 / 5.0

Subtask #2 15.0 / 15.0

Subtask #3 10.0 / 10.0

Subtask #4 40.0 / 40.0

Subtask #5 30.0 / 30.0

Subtask #1
5.0 / 5.0

Subtask #2
15.0 / 15.0

Subtask #3
10.0 / 10.0

Subtask #4
40.0 / 40.0

Subtask #5
30.0 / 30.0