oj.uz

Submission #898040

# Submission time Handle Problem Language Result Execution time Memory
898040 2024-01-04T08:51:24 Z LCJLY The Xana coup (BOI21_xanadu) C++14
100 / 100
 59 ms 23632 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)1e14,(int)1e14};
	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>1e13){
		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 2 ms 6492 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6492 KB Output is correct
5 Correct 2 ms 6744 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6492 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6492 KB Output is correct
5 Correct 2 ms 6744 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 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 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 2 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 59 ms 23108 KB Output is correct
2 Correct 44 ms 22864 KB Output is correct
3 Correct 40 ms 23236 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 23080 KB Output is correct
2 Correct 37 ms 22868 KB Output is correct
3 Correct 38 ms 23388 KB Output is correct
4 Correct 31 ms 10844 KB Output is correct
5 Correct 35 ms 11836 KB Output is correct
6 Correct 37 ms 11912 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 12 ms 8284 KB Output is correct
9 Correct 52 ms 11884 KB Output is correct
10 Correct 34 ms 11644 KB Output is correct
11 Correct 38 ms 12372 KB Output is correct
12 Correct 40 ms 12624 KB Output is correct
13 Correct 36 ms 11864 KB Output is correct
14 Correct 33 ms 12196 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6492 KB Output is correct
2 Correct 2 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6492 KB Output is correct
5 Correct 2 ms 6744 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 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 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 2 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 59 ms 23108 KB Output is correct
18 Correct 44 ms 22864 KB Output is correct
19 Correct 40 ms 23236 KB Output is correct
20 Correct 38 ms 23080 KB Output is correct
21 Correct 37 ms 22868 KB Output is correct
22 Correct 38 ms 23388 KB Output is correct
23 Correct 31 ms 10844 KB Output is correct
24 Correct 35 ms 11836 KB Output is correct
25 Correct 37 ms 11912 KB Output is correct
26 Correct 2 ms 6492 KB Output is correct
27 Correct 12 ms 8284 KB Output is correct
28 Correct 52 ms 11884 KB Output is correct
29 Correct 34 ms 11644 KB Output is correct
30 Correct 38 ms 12372 KB Output is correct
31 Correct 40 ms 12624 KB Output is correct
32 Correct 36 ms 11864 KB Output is correct
33 Correct 33 ms 12196 KB Output is correct
34 Correct 2 ms 6788 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 6492 KB Output is correct
38 Correct 2 ms 6492 KB Output is correct
39 Correct 2 ms 6492 KB Output is correct
40 Correct 2 ms 6492 KB Output is correct
41 Correct 2 ms 6492 KB Output is correct
42 Correct 2 ms 6492 KB Output is correct
43 Correct 2 ms 6488 KB Output is correct
44 Correct 2 ms 6488 KB Output is correct
45 Correct 41 ms 23376 KB Output is correct
46 Correct 39 ms 23376 KB Output is correct
47 Correct 38 ms 23632 KB Output is correct
48 Correct 37 ms 11344 KB Output is correct
49 Correct 36 ms 11780 KB Output is correct
50 Correct 34 ms 11860 KB Output is correct
51 Correct 2 ms 6492 KB Output is correct
52 Correct 13 ms 8284 KB Output is correct
53 Correct 40 ms 11720 KB Output is correct
54 Correct 37 ms 11860 KB Output is correct
55 Correct 33 ms 12368 KB Output is correct
56 Correct 37 ms 12628 KB Output is correct
57 Correct 32 ms 11868 KB Output is correct
58 Correct 34 ms 12380 KB Output is correct
59 Correct 13 ms 8280 KB Output is correct
60 Correct 30 ms 11092 KB Output is correct
61 Correct 47 ms 11672 KB Output is correct
62 Correct 51 ms 12112 KB Output is correct
63 Correct 35 ms 11712 KB Output is correct
64 Correct 33 ms 11600 KB Output is correct
65 Correct 32 ms 12112 KB Output is correct
66 Correct 30 ms 12180 KB Output is correct
67 Correct 30 ms 11976 KB Output is correct
68 Correct 28 ms 11980 KB Output is correct
69 Correct 27 ms 11984 KB Output is correct
70 Correct 29 ms 11984 KB Output is correct