oj.uz

Submission #897415

# Submission time Handle Problem Language Result Execution time Memory
897415 2024-01-03T04:28:06 Z LCJLY The Xana coup (BOI21_xanadu) C++14
100 / 100
 67 ms 23332 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;

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

void dfs(int index, int par){
	array<int,2>cnt;
	array<int,2>take;
	array<int,2>change;
	cnt={0,0};
	take={0,0};
	change={(int)1e15,(int)1e15};
	
	
	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
				take[x]+=dp[0][x][it];
				change[x]=min(change[x],dp[1][x][it]-dp[0][x][it]);
				//change from no toggle to toggle
			}
			else{
				//toggle is better
				take[x]+=dp[1][x][it];
				cnt[x]++;
				change[x]=min(change[x],dp[0][x][it]-dp[1][x][it]);
				//change from toggle to no toggle
			}
		}
	}
	
	int bit=arr[index];
	
	//to achieve 0 0 (no toggle, and value is 0) need to take all 0 from child, but if toggle odd number of times, then fix back
	//by toggling one less child or one more child
	dp[0][0][index]=take[0]+((cnt[0]+bit)%2?change[0]:0);
	//to achieve 0 1 (no toggle and value is 1) need take all 0 from child, but if toggle even number of times then fix back
	dp[0][1][index]=take[0]+(!((cnt[0]+bit)%2)?change[0]:0);
	dp[1][0][index]=1+take[1]+(!((cnt[1]+bit)%2)?change[1]:0);
	dp[1][1][index]=1+take[1]+((cnt[1]+bit)%2?change[1]:0);	
}

void solve(){	
	int n;
	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 best=min(dp[0][0][1],dp[1][0][1]); //force this node to be 0, invert works when normal works
	if(best>=1e12) cout << "impossible\n";
	else cout << best;
}
 
int32_t main(){										
	ios::sync_with_stdio(0);	
	cin.tie(0);
	//freopen("tribool.in", "r", stdin);
	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 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 6488 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 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 6488 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 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct
11 Correct 2 ms 6516 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 6412 KB Output is correct
15 Correct 2 ms 6488 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 67 ms 22168 KB Output is correct
2 Correct 44 ms 21900 KB Output is correct
3 Correct 58 ms 23332 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 55 ms 22080 KB Output is correct
2 Correct 36 ms 21844 KB Output is correct
3 Correct 42 ms 23176 KB Output is correct
4 Correct 57 ms 11044 KB Output is correct
5 Correct 46 ms 11604 KB Output is correct
6 Correct 40 ms 11612 KB Output is correct
7 Correct 2 ms 6492 KB Output is correct
8 Correct 14 ms 8276 KB Output is correct
9 Correct 46 ms 11448 KB Output is correct
10 Correct 44 ms 11420 KB Output is correct
11 Correct 51 ms 12184 KB Output is correct
12 Correct 55 ms 12372 KB Output is correct
13 Correct 33 ms 11356 KB Output is correct
14 Correct 37 ms 11836 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 6488 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 6492 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct
11 Correct 2 ms 6516 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 6412 KB Output is correct
15 Correct 2 ms 6488 KB Output is correct
16 Correct 2 ms 6492 KB Output is correct
17 Correct 67 ms 22168 KB Output is correct
18 Correct 44 ms 21900 KB Output is correct
19 Correct 58 ms 23332 KB Output is correct
20 Correct 55 ms 22080 KB Output is correct
21 Correct 36 ms 21844 KB Output is correct
22 Correct 42 ms 23176 KB Output is correct
23 Correct 57 ms 11044 KB Output is correct
24 Correct 46 ms 11604 KB Output is correct
25 Correct 40 ms 11612 KB Output is correct
26 Correct 2 ms 6492 KB Output is correct
27 Correct 14 ms 8276 KB Output is correct
28 Correct 46 ms 11448 KB Output is correct
29 Correct 44 ms 11420 KB Output is correct
30 Correct 51 ms 12184 KB Output is correct
31 Correct 55 ms 12372 KB Output is correct
32 Correct 33 ms 11356 KB Output is correct
33 Correct 37 ms 11836 KB Output is correct
34 Correct 2 ms 6748 KB Output is correct
35 Correct 1 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 6532 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 6492 KB Output is correct
45 Correct 50 ms 23184 KB Output is correct
46 Correct 44 ms 22868 KB Output is correct
47 Correct 50 ms 23212 KB Output is correct
48 Correct 50 ms 11052 KB Output is correct
49 Correct 57 ms 11472 KB Output is correct
50 Correct 38 ms 11604 KB Output is correct
51 Correct 2 ms 6492 KB Output is correct
52 Correct 13 ms 8320 KB Output is correct
53 Correct 39 ms 11444 KB Output is correct
54 Correct 37 ms 11468 KB Output is correct
55 Correct 48 ms 12084 KB Output is correct
56 Correct 50 ms 12368 KB Output is correct
57 Correct 38 ms 11460 KB Output is correct
58 Correct 39 ms 11900 KB Output is correct
59 Correct 12 ms 8180 KB Output is correct
60 Correct 33 ms 10772 KB Output is correct
61 Correct 39 ms 11312 KB Output is correct
62 Correct 37 ms 11448 KB Output is correct
63 Correct 63 ms 11348 KB Output is correct
64 Correct 40 ms 11600 KB Output is correct
65 Correct 33 ms 11860 KB Output is correct
66 Correct 34 ms 11868 KB Output is correct
67 Correct 28 ms 11472 KB Output is correct
68 Correct 27 ms 11472 KB Output is correct
69 Correct 41 ms 11464 KB Output is correct
70 Correct 29 ms 11612 KB Output is correct