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Submission #677073

# Submission time Handle Problem Language Result Execution time Memory
677073 2023-01-02T08:35:48 Z ajab_01 The Xana coup (BOI21_xanadu) C++17
100 / 100
 74 ms 19192 KB 
#include<bits/stdc++.h>
using namespace std;

#define int long long

const int N = 1e5 + 5;
const int INF = 1e12;
vector<int> g[N];
int dp[N][2][2] , sit[N] , root , n;

void dfs(int ver , int par){
	for(int i : g[ver]){
		if(i == par) continue;
		dfs(i , ver);
	}

	if((int)g[ver].size() == 1){
		dp[ver][sit[ver]][0] = 0;
		dp[ver][sit[ver] ^ 1][1] = 1;
		return;
	}

	int sum1 = 0 , sum2 = 0 , cnt1 = 0 , cnt2 = 0 , rem1 = INF , rem2 = INF;
	for(int i : g[ver]){
		if(i == par) continue;
		sum1 += min(dp[i][0][1] , dp[i][0][0]);
		sum2 += min(dp[i][1][1] , dp[i][1][0]);
		rem1 = min(rem1 , max(dp[i][0][1] , dp[i][0][0]) - min(dp[i][0][1] , dp[i][0][0]));
		rem2 = min(rem2 , max(dp[i][1][1] , dp[i][1][0]) - min(dp[i][1][1] , dp[i][1][0]));
		if(dp[i][0][1] <= dp[i][0][0]) cnt1++;
		if(dp[i][1][1] <= dp[i][1][0]) cnt2++; 
	}

	for(int k = 0 ; k < 2 ; k++){
		if(k == 1){
			dp[ver][sit[ver]][k] = min(dp[ver][sit[ver]][k] , sum2 + (cnt2 & 1 ? 0 : rem2) + 1);
			dp[ver][sit[ver] ^ 1][k] = min(dp[ver][sit[ver] ^ 1][k] , sum2 + (cnt2 & 1 ? rem2 : 0) + 1);
		}
		else{
			dp[ver][sit[ver]][k] = min(dp[ver][sit[ver]][k] , sum1 + (cnt1 & 1 ? rem1 : 0));
			dp[ver][sit[ver] ^ 1][k] = min(dp[ver][sit[ver] ^ 1][k] , sum1 + (cnt1 & 1 ? 0 : rem1));
		}
	}
}

int32_t main(){
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	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);
		if((int)g[v].size() > 1) root = v;
		if((int)g[u].size() > 1) root = u;
	}

	for(int i = 0 ; i < n ; i++)
		cin >> sit[i];

	for(int i = 0 ; i < n ; i++)
		for(int j = 0 ; j < 2 ; j++)
			for(int k = 0 ; k < 2 ; k++)
				dp[i][j][k] = INF;

	dfs(root , -1);

	int ans = min(dp[root][0][1] , dp[root][0][0]);
	if(ans > n) cout << "impossible" << '\n';
	else cout << ans << '\n';
	return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 2 ms 2684 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2676 KB Output is correct
11 Correct 1 ms 2676 KB Output is correct
12 Correct 1 ms 2680 KB Output is correct
13 Correct 1 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2684 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 59 ms 18064 KB Output is correct
2 Correct 53 ms 18744 KB Output is correct
3 Correct 49 ms 19148 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 18072 KB Output is correct
2 Correct 49 ms 18788 KB Output is correct
3 Correct 51 ms 19192 KB Output is correct
4 Correct 49 ms 10244 KB Output is correct
5 Correct 50 ms 11084 KB Output is correct
6 Correct 55 ms 11240 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 15 ms 5624 KB Output is correct
9 Correct 57 ms 10936 KB Output is correct
10 Correct 60 ms 11044 KB Output is correct
11 Correct 54 ms 11676 KB Output is correct
12 Correct 58 ms 11880 KB Output is correct
13 Correct 56 ms 11132 KB Output is correct
14 Correct 73 ms 11580 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 2 ms 2684 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2676 KB Output is correct
11 Correct 1 ms 2676 KB Output is correct
12 Correct 1 ms 2680 KB Output is correct
13 Correct 1 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2684 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct
17 Correct 59 ms 18064 KB Output is correct
18 Correct 53 ms 18744 KB Output is correct
19 Correct 49 ms 19148 KB Output is correct
20 Correct 57 ms 18072 KB Output is correct
21 Correct 49 ms 18788 KB Output is correct
22 Correct 51 ms 19192 KB Output is correct
23 Correct 49 ms 10244 KB Output is correct
24 Correct 50 ms 11084 KB Output is correct
25 Correct 55 ms 11240 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Correct 15 ms 5624 KB Output is correct
28 Correct 57 ms 10936 KB Output is correct
29 Correct 60 ms 11044 KB Output is correct
30 Correct 54 ms 11676 KB Output is correct
31 Correct 58 ms 11880 KB Output is correct
32 Correct 56 ms 11132 KB Output is correct
33 Correct 73 ms 11580 KB Output is correct
34 Correct 2 ms 2644 KB Output is correct
35 Correct 1 ms 2680 KB Output is correct
36 Correct 1 ms 2644 KB Output is correct
37 Correct 2 ms 2644 KB Output is correct
38 Correct 2 ms 2644 KB Output is correct
39 Correct 1 ms 2656 KB Output is correct
40 Correct 2 ms 2644 KB Output is correct
41 Correct 2 ms 2644 KB Output is correct
42 Correct 2 ms 2676 KB Output is correct
43 Correct 2 ms 2644 KB Output is correct
44 Correct 3 ms 2644 KB Output is correct
45 Correct 50 ms 18252 KB Output is correct
46 Correct 53 ms 18816 KB Output is correct
47 Correct 51 ms 19148 KB Output is correct
48 Correct 49 ms 10192 KB Output is correct
49 Correct 55 ms 11020 KB Output is correct
50 Correct 65 ms 11108 KB Output is correct
51 Correct 2 ms 2644 KB Output is correct
52 Correct 16 ms 5612 KB Output is correct
53 Correct 62 ms 10700 KB Output is correct
54 Correct 63 ms 10828 KB Output is correct
55 Correct 55 ms 11468 KB Output is correct
56 Correct 74 ms 11640 KB Output is correct
57 Correct 52 ms 10884 KB Output is correct
58 Correct 55 ms 11328 KB Output is correct
59 Correct 14 ms 5588 KB Output is correct
60 Correct 46 ms 10008 KB Output is correct
61 Correct 55 ms 10544 KB Output is correct
62 Correct 57 ms 10768 KB Output is correct
63 Correct 58 ms 10832 KB Output is correct
64 Correct 61 ms 10792 KB Output is correct
65 Correct 47 ms 11212 KB Output is correct
66 Correct 54 ms 11264 KB Output is correct
67 Correct 37 ms 10900 KB Output is correct
68 Correct 42 ms 10972 KB Output is correct
69 Correct 38 ms 10888 KB Output is correct
70 Correct 36 ms 10920 KB Output is correct