oj.uz

Submission #936150

# Submission time Handle Problem Language Result Execution time Memory
936150 2024-03-01T09:26:56 Z shoryu386 The Xana coup (BOI21_xanadu) C++17
100 / 100
 112 ms 25232 KB 
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define MAX 100007
int n;
vector<int> adj[MAX];

int dp[MAX][2][2];
int active[MAX];

bool comp(pair<int, int> a, pair<int, int> b){
	return a.second - a.first < b.second - b.first;
}

void dfs(int x, int p){
	for (auto y : adj[x]){ if (y == p) continue;
		dfs(y, x);
	}
	
	//we want to find the min presses to make even, and min presses to make odd
	if (true){
		vector<pair<int, int>> competition;
		int cursum = 0;
		for (auto y : adj[x]){ if (y == p) continue;
			competition.push_back({dp[y][0][0], dp[y][1][0]});
			cursum += dp[y][0][0];
		}
		
		int evenbest = cursum, oddbest = INT_MAX;
		sort(competition.begin(), competition.end(), comp);
		
		bool cureven = true;
		for (auto y : competition){
			cureven = !cureven;
			cursum += y.second - y.first;
			
			if (cureven) evenbest = min(evenbest, cursum);
			else oddbest = min(oddbest, cursum);
		}
		
		if (active[x]){
			dp[x][0][0] = oddbest;
			dp[x][0][1] = evenbest;
		}
		else{
			dp[x][0][0] = evenbest;
			dp[x][0][1] = oddbest;
		}
	}
	if (true){
		vector<pair<int, int>> competition;
		int cursum = 0;
		for (auto y : adj[x]){ if (y == p) continue;
			competition.push_back({dp[y][0][1], dp[y][1][1]});
			cursum += dp[y][0][1];
		}
		
		int evenbest = cursum, oddbest = INT_MAX;
		sort(competition.begin(), competition.end(), comp);
		
		bool cureven = true;
		for (auto y : competition){
			cureven = !cureven;
			cursum += y.second - y.first;
			
			if (cureven) evenbest = min(evenbest, cursum);
			else oddbest = min(oddbest, cursum);
		}
		
		if (active[x]){
			dp[x][1][0] = evenbest + 1;
			dp[x][1][1] = oddbest + 1;
		}
		else{
			dp[x][1][0] = oddbest + 1;
			dp[x][1][1] = evenbest + 1;
		}
	}
	
	//cout << x << ' ' << dp[x][0] << ' ' << dp[x][1] << '\n';
}

main(){
	cin >> n;
	for (int x = 0; x < n-1; x++){
		int a, b; cin >> a >> b; a--; b--; adj[a].push_back(b); adj[b].push_back(a);
	}
	for (int x = 0; x < n; x++) cin >> active[x];
	
	dfs(0, -1);
	
	int res = min(dp[0][0][0], dp[0][1][0]);
	
	if (res >= INT_MAX) cout << "impossible";
	else cout << res;
	
}

Compilation message

xanadu.cpp:84:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   84 | main(){
      | ^~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6900 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 1 ms 6492 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6900 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 1 ms 6492 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 2 ms 6492 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 2 ms 6532 KB Output is correct
9 Correct 2 ms 6492 KB Output is correct
10 Correct 2 ms 6520 KB Output is correct
11 Correct 2 ms 6492 KB Output is correct
12 Correct 2 ms 6492 KB Output is correct
13 Correct 2 ms 6492 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6492 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 79 ms 23700 KB Output is correct
2 Correct 78 ms 24912 KB Output is correct
3 Correct 81 ms 25168 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 105 ms 23644 KB Output is correct
2 Correct 78 ms 24916 KB Output is correct
3 Correct 81 ms 25172 KB Output is correct
4 Correct 81 ms 11348 KB Output is correct
5 Correct 74 ms 11912 KB Output is correct
6 Correct 77 ms 11968 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 28 ms 8440 KB Output is correct
9 Correct 76 ms 11492 KB Output is correct
10 Correct 84 ms 11860 KB Output is correct
11 Correct 74 ms 12624 KB Output is correct
12 Correct 77 ms 12712 KB Output is correct
13 Correct 73 ms 11780 KB Output is correct
14 Correct 75 ms 12120 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6900 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 1 ms 6492 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 2 ms 6492 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 2 ms 6532 KB Output is correct
9 Correct 2 ms 6492 KB Output is correct
10 Correct 2 ms 6520 KB Output is correct
11 Correct 2 ms 6492 KB Output is correct
12 Correct 2 ms 6492 KB Output is correct
13 Correct 2 ms 6492 KB Output is correct
14 Correct 1 ms 6492 KB Output is correct
15 Correct 1 ms 6492 KB Output is correct
16 Correct 1 ms 6492 KB Output is correct
17 Correct 79 ms 23700 KB Output is correct
18 Correct 78 ms 24912 KB Output is correct
19 Correct 81 ms 25168 KB Output is correct
20 Correct 105 ms 23644 KB Output is correct
21 Correct 78 ms 24916 KB Output is correct
22 Correct 81 ms 25172 KB Output is correct
23 Correct 81 ms 11348 KB Output is correct
24 Correct 74 ms 11912 KB Output is correct
25 Correct 77 ms 11968 KB Output is correct
26 Correct 2 ms 6492 KB Output is correct
27 Correct 28 ms 8440 KB Output is correct
28 Correct 76 ms 11492 KB Output is correct
29 Correct 84 ms 11860 KB Output is correct
30 Correct 74 ms 12624 KB Output is correct
31 Correct 77 ms 12712 KB Output is correct
32 Correct 73 ms 11780 KB Output is correct
33 Correct 75 ms 12120 KB Output is correct
34 Correct 2 ms 6488 KB Output is correct
35 Correct 2 ms 6492 KB Output is correct
36 Correct 2 ms 6492 KB Output is correct
37 Correct 2 ms 6524 KB Output is correct
38 Correct 2 ms 6492 KB Output is correct
39 Correct 1 ms 6492 KB Output is correct
40 Correct 1 ms 6492 KB Output is correct
41 Correct 2 ms 6492 KB Output is correct
42 Correct 1 ms 6492 KB Output is correct
43 Correct 2 ms 6492 KB Output is correct
44 Correct 2 ms 6492 KB Output is correct
45 Correct 102 ms 24948 KB Output is correct
46 Correct 82 ms 24912 KB Output is correct
47 Correct 79 ms 25232 KB Output is correct
48 Correct 66 ms 11256 KB Output is correct
49 Correct 76 ms 11700 KB Output is correct
50 Correct 80 ms 12032 KB Output is correct
51 Correct 2 ms 6492 KB Output is correct
52 Correct 25 ms 8272 KB Output is correct
53 Correct 76 ms 11620 KB Output is correct
54 Correct 88 ms 11872 KB Output is correct
55 Correct 75 ms 12668 KB Output is correct
56 Correct 77 ms 12884 KB Output is correct
57 Correct 70 ms 11852 KB Output is correct
58 Correct 112 ms 12076 KB Output is correct
59 Correct 25 ms 8276 KB Output is correct
60 Correct 66 ms 11188 KB Output is correct
61 Correct 82 ms 11444 KB Output is correct
62 Correct 76 ms 11604 KB Output is correct
63 Correct 80 ms 11784 KB Output is correct
64 Correct 85 ms 11600 KB Output is correct
65 Correct 73 ms 12212 KB Output is correct
66 Correct 71 ms 12112 KB Output is correct
67 Correct 76 ms 15460 KB Output is correct
68 Correct 73 ms 15400 KB Output is correct
69 Correct 78 ms 15420 KB Output is correct
70 Correct 73 ms 15436 KB Output is correct