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Submission #848831

# Submission time Handle Problem Language Result Execution time Memory
848831 2023-09-13T14:53:22 Z TAhmed33 The Xana coup (BOI21_xanadu) C++
100 / 100
 107 ms 22864 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MAXN = 1e5 + 25;
vector <int> adj[MAXN];
bool ok[MAXN];
int dp[MAXN][2][2], n;
int ans (int pos, int par, int x, int y) {
	int &ret = dp[pos][x][y];
	if (ret != -1) return ret;
	if (adj[pos].size() == 1 && par != -1) {
		if (ok[pos] ^ x ^ y) {
			return ret = 1e9;
		}
		return ret = y;
	}
	int p[2] = {}; //subset which adds even parity
	int q[2] = {}; //subset which adds odd parity
	int cnt = 0;
	for (auto i : adj[pos]) {
		if (i == par) continue;
		cnt++;
		if (cnt == 1) {
			q[0] = ans(i, pos, y, 1);
			p[0] = ans(i, pos, y, 0);
			continue;
		}
		p[1] = min(ans(i, pos, y, 0) + p[0], ans(i, pos, y, 1) + q[0]);
		q[1] = min(ans(i, pos, y, 0) + q[0], ans(i, pos, y, 1) + p[0]);
		q[0] = q[1]; p[0] = p[1];
	}
	bool i = ok[pos] ^ x ^ y;
	if (i) return ret = y + q[0];
	else return ret = y + p[0];
}
signed main () {
	memset(dp, -1, sizeof(dp));
	cin >> n;
	for (int i = 1; i < n; i++) {
		int a, b;
		cin >> a >> b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	for (int i = 1; i <= n; i++) cin >> ok[i];
	int x = min(ans(1, -1, 0, 0), ans(1, -1, 0, 1));
	if (x <= n) {
		cout << x << '\n';
	} else {
		cout << "impossible\n";
	}
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 5976 KB Output is correct
2 Correct 1 ms 5976 KB Output is correct
3 Correct 2 ms 5980 KB Output is correct
4 Correct 1 ms 5980 KB Output is correct
5 Correct 1 ms 5976 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 5976 KB Output is correct
2 Correct 1 ms 5976 KB Output is correct
3 Correct 2 ms 5980 KB Output is correct
4 Correct 1 ms 5980 KB Output is correct
5 Correct 1 ms 5976 KB Output is correct
6 Correct 2 ms 5976 KB Output is correct
7 Correct 2 ms 5976 KB Output is correct
8 Correct 1 ms 5976 KB Output is correct
9 Correct 2 ms 5976 KB Output is correct
10 Correct 2 ms 5976 KB Output is correct
11 Correct 2 ms 5976 KB Output is correct
12 Correct 1 ms 5976 KB Output is correct
13 Correct 2 ms 5976 KB Output is correct
14 Correct 1 ms 5980 KB Output is correct
15 Correct 2 ms 5976 KB Output is correct
16 Correct 2 ms 6232 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 77 ms 22800 KB Output is correct
2 Correct 74 ms 22680 KB Output is correct
3 Correct 76 ms 22864 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 74 ms 22728 KB Output is correct
2 Correct 86 ms 22608 KB Output is correct
3 Correct 76 ms 22864 KB Output is correct
4 Correct 64 ms 10580 KB Output is correct
5 Correct 73 ms 11088 KB Output is correct
6 Correct 88 ms 11488 KB Output is correct
7 Correct 2 ms 5976 KB Output is correct
8 Correct 25 ms 7696 KB Output is correct
9 Correct 94 ms 11100 KB Output is correct
10 Correct 78 ms 11088 KB Output is correct
11 Correct 71 ms 11856 KB Output is correct
12 Correct 74 ms 11856 KB Output is correct
13 Correct 70 ms 11272 KB Output is correct
14 Correct 107 ms 11600 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 5976 KB Output is correct
2 Correct 1 ms 5976 KB Output is correct
3 Correct 2 ms 5980 KB Output is correct
4 Correct 1 ms 5980 KB Output is correct
5 Correct 1 ms 5976 KB Output is correct
6 Correct 2 ms 5976 KB Output is correct
7 Correct 2 ms 5976 KB Output is correct
8 Correct 1 ms 5976 KB Output is correct
9 Correct 2 ms 5976 KB Output is correct
10 Correct 2 ms 5976 KB Output is correct
11 Correct 2 ms 5976 KB Output is correct
12 Correct 1 ms 5976 KB Output is correct
13 Correct 2 ms 5976 KB Output is correct
14 Correct 1 ms 5980 KB Output is correct
15 Correct 2 ms 5976 KB Output is correct
16 Correct 2 ms 6232 KB Output is correct
17 Correct 77 ms 22800 KB Output is correct
18 Correct 74 ms 22680 KB Output is correct
19 Correct 76 ms 22864 KB Output is correct
20 Correct 74 ms 22728 KB Output is correct
21 Correct 86 ms 22608 KB Output is correct
22 Correct 76 ms 22864 KB Output is correct
23 Correct 64 ms 10580 KB Output is correct
24 Correct 73 ms 11088 KB Output is correct
25 Correct 88 ms 11488 KB Output is correct
26 Correct 2 ms 5976 KB Output is correct
27 Correct 25 ms 7696 KB Output is correct
28 Correct 94 ms 11100 KB Output is correct
29 Correct 78 ms 11088 KB Output is correct
30 Correct 71 ms 11856 KB Output is correct
31 Correct 74 ms 11856 KB Output is correct
32 Correct 70 ms 11272 KB Output is correct
33 Correct 107 ms 11600 KB Output is correct
34 Correct 1 ms 5976 KB Output is correct
35 Correct 1 ms 5976 KB Output is correct
36 Correct 2 ms 5976 KB Output is correct
37 Correct 2 ms 5976 KB Output is correct
38 Correct 2 ms 5976 KB Output is correct
39 Correct 2 ms 5976 KB Output is correct
40 Correct 2 ms 6180 KB Output is correct
41 Correct 2 ms 5976 KB Output is correct
42 Correct 1 ms 5976 KB Output is correct
43 Correct 1 ms 5976 KB Output is correct
44 Correct 1 ms 5976 KB Output is correct
45 Correct 73 ms 22864 KB Output is correct
46 Correct 72 ms 22608 KB Output is correct
47 Correct 86 ms 22756 KB Output is correct
48 Correct 63 ms 10576 KB Output is correct
49 Correct 70 ms 11092 KB Output is correct
50 Correct 72 ms 11340 KB Output is correct
51 Correct 2 ms 5976 KB Output is correct
52 Correct 25 ms 7656 KB Output is correct
53 Correct 72 ms 10832 KB Output is correct
54 Correct 71 ms 11092 KB Output is correct
55 Correct 85 ms 11620 KB Output is correct
56 Correct 73 ms 11856 KB Output is correct
57 Correct 67 ms 11272 KB Output is correct
58 Correct 70 ms 11400 KB Output is correct
59 Correct 24 ms 7516 KB Output is correct
60 Correct 67 ms 10440 KB Output is correct
61 Correct 73 ms 10832 KB Output is correct
62 Correct 107 ms 11088 KB Output is correct
63 Correct 72 ms 11088 KB Output is correct
64 Correct 76 ms 10832 KB Output is correct
65 Correct 66 ms 11532 KB Output is correct
66 Correct 72 ms 11344 KB Output is correct
67 Correct 75 ms 11192 KB Output is correct
68 Correct 69 ms 11460 KB Output is correct
69 Correct 75 ms 11208 KB Output is correct
70 Correct 73 ms 11204 KB Output is correct