oj.uz

Submission #898038

# Submission time Handle Problem Language Result Execution time Memory
898038 2024-01-04T08:50:26 Z LCJLY The Xana coup (BOI21_xanadu) C++14
30 / 100
 52 ms 23636 KB 
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define ld long double
#define show(x,y) //cout << y << " " << #x << endl;
#define show2(x,y,i,j) //cout << y << " " << #x << "  " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) //cout << y << " " << #x << "  " << j << " " << #i << "  " << q << " " << #p << endl; 
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;

int n;
vector<int>adj[100005];
int arr[100005];
int dp[2][2][100005];

void dfs(int index, int par){
	array<int,2>counter;
	array<int,2>change;
	array<int,2>cnt;
	change={(int)1e16,(int)1e16};
	cnt={0,0};
	counter={0,0};
	for(auto it:adj[index]){
		if(it==par) continue;
		dfs(it,index);
		for(int x=0;x<2;x++){
			if(dp[0][x][it]<dp[1][x][it]){
				//no toggle is better
				counter[x]+=dp[0][x][it];
				change[x]=min(change[x],dp[1][x][it]-dp[0][x][it]);
			}
			else{
				//toggle is better
				counter[x]+=dp[1][x][it];
				change[x]=min(change[x],dp[0][x][it]-dp[1][x][it]);
				cnt[x]++;
			}
		}
	}
	
	//no toggle remain 0
	dp[0][0][index]=counter[0]+ ((cnt[0]^arr[index])%2? change[0]:0);
	dp[0][1][index]=counter[0]+((cnt[0]^arr[index])%2==0?change[0]:0);
	dp[1][0][index]=1+counter[1]+((cnt[1]^arr[index])%2==0?change[1]:0);
	dp[1][1][index]=1+counter[1]+((cnt[1]^arr[index])%2?change[1]:0);
}

void solve(){	
	cin >> n;
	
	int temp,temp2;
	for(int x=0;x<n-1;x++){
		cin >> temp >> temp2;
		adj[temp].push_back(temp2);
		adj[temp2].push_back(temp);
	}
	
	for(int x=1;x<=n;x++){
		cin >> arr[x];
	}
	
	dfs(1,-1);
	int hold=min(dp[1][0][1],dp[0][0][1]);
	if(hold>1e12){
		cout << "impossible\n";
	}
	else cout << hold;
	
	
}
 
int32_t main(){										
	ios::sync_with_stdio(0);	
	cin.tie(0);
	//freopen("redistricting.in", "r", stdin);
	//freopen("redistricting.out", "w", stdout);
	int t=1;
	//cin >> t;
	while(t--){
		solve();
	}	
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 2 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 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 2 ms 6492 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 1 ms 6492 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 2 ms 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 3 ms 6492 KB Output is correct
11 Correct 2 ms 6488 KB Output is correct
12 Correct 1 ms 6492 KB Output is correct
13 Correct 2 ms 6492 KB Output is correct
14 Correct 2 ms 6492 KB Output is correct
15 Correct 2 ms 6492 KB Output is correct
16 Correct 2 ms 6492 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 23440 KB Output is correct
2 Correct 37 ms 23268 KB Output is correct
3 Correct 43 ms 23468 KB Output is correct

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 52 ms 23472 KB Output is correct
2 Correct 42 ms 23156 KB Output is correct
3 Correct 39 ms 23636 KB Output is correct
4 Incorrect 30 ms 11472 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 1 ms 6492 KB Output is correct
4 Correct 2 ms 6492 KB Output is correct
5 Correct 2 ms 6492 KB Output is correct
6 Correct 1 ms 6492 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 2 ms 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 3 ms 6492 KB Output is correct
11 Correct 2 ms 6488 KB Output is correct
12 Correct 1 ms 6492 KB Output is correct
13 Correct 2 ms 6492 KB Output is correct
14 Correct 2 ms 6492 KB Output is correct
15 Correct 2 ms 6492 KB Output is correct
16 Correct 2 ms 6492 KB Output is correct
17 Correct 38 ms 23440 KB Output is correct
18 Correct 37 ms 23268 KB Output is correct
19 Correct 43 ms 23468 KB Output is correct
20 Correct 52 ms 23472 KB Output is correct
21 Correct 42 ms 23156 KB Output is correct
22 Correct 39 ms 23636 KB Output is correct
23 Incorrect 30 ms 11472 KB Output isn't correct
24 Halted 0 ms 0 KB -