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Submission #867016

# Submission time Handle Problem Language Result Execution time Memory
867016 2023-10-27T15:11:11 Z Ahmed_Solyman The Xana coup (BOI21_xanadu) C++14
50 / 100
 81 ms 21852 KB 
/*
In the name of Allah
made by: Ahmed_Solyman
*/
#include <bits/stdc++.h>
#include <ext/rope>
 
using namespace std;
using namespace __gnu_cxx;
#pragma GCC optimize("-Ofast")
#pragma GCC optimize("-O1")
//-------------------------------------------------------------//
typedef long long ll;
typedef unsigned long long ull;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PI acos(-1)
#define lb lower_bound
#define ub upper_bound
#define endl '\n'
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define sum_to(n) (n*(n+1))/2
#define pb push_back
#define pf push_front
#define fil(arr,x) memset(arr,x,sizeof(arr))
const ll mod=1e9+7;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,-1,1};
//-------------------------------------------------------------//
ll lcm(ll a,ll b)
{
    return (max(a,b)/__gcd(a,b))*min(a,b);
}
void person_bool(bool x)
{
    cout<<(x?"YES":"NO")<<endl;
}
const int N=1e5+5;
vector<int>adj[N],color(N);
ll n,dp[N][2][2];
ll solve(int i,int c,int rev,int p){
	ll &ret=dp[i][c][rev];
	if(~ret)return ret;
	if(adj[i].size()==1 && i!=1){
		if(c==1){
			return ret=1e9;
		}
		else{
			return ret=rev;
		}
	}
	int opt=0;
	bool flag=0;
	ll sum=rev;
	for(auto ch:adj[i]){
		if(ch!=p){
			ll a=solve(ch,rev^color[ch],0,i);
			ll b=solve(ch,1^rev^color[ch],1,i);
			sum+=min(a,b);
			if(a==b){
				flag=1;
			}
			else if(a>b){
				++opt;
			}
		}
	}
	if(flag){
		ret=rev;
		for(auto ch:adj[i]){
			if(ch!=p){
				ret+=min(solve(ch,rev^color[ch],0,i),solve(ch,1^rev^color[ch],1,i));
			}
		}
		ret=min(ret,1000000000LL);
		return ret;
	}
	else{
		ret=1e9;
		for(auto ch:adj[i]){
			if(ch!=p){
				ll a=solve(ch,rev^color[ch],0,i);
				ll b=solve(ch,1^rev^color[ch],1,i);
				int u=opt-(a>b);
				if(c^u==0){
					ret=min(ret,sum-min(a,b)+a);
				}
				else{
					ret=min(ret,sum-min(a,b)+b);
				}
			}
		}
		return ret;
	}
	return ret;
}
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    #ifndef ONLINE_JUDGE
    //freopen("input.in", "r", stdin);
    //freopen("output.out", "w", stdout);
    #endif
    fast
    fil(dp,-1);
    int n;cin>>n;
    for(int i=0;i<n-1;i++){
    	int u,v;cin>>u>>v;
    	adj[u].push_back(v);
    	adj[v].push_back(u);
    }
    for(int i=1;i<=n;i++)cin>>color[i];
    ll ans=solve(1,color[1],0,0);
	fil(dp,-1);
	ans=min(ans,solve(1,!color[1],1,0));
	if(ans>=1e9){
		cout<<"impossible"<<endl;
	}
    else cout<<ans<<endl;
    return 0;
}

Compilation message

xanadu.cpp: In function 'll solve(int, int, int, int)':
xanadu.cpp:85:11: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   85 |     if(c^u==0){
      |          ~^~~

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6232 KB Output is correct
2 Incorrect 2 ms 6236 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6232 KB Output is correct
2 Incorrect 2 ms 6236 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 59 ms 21852 KB Output is correct
2 Correct 58 ms 21540 KB Output is correct
3 Correct 59 ms 21844 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 72 ms 21840 KB Output is correct
2 Correct 56 ms 21584 KB Output is correct
3 Correct 59 ms 21840 KB Output is correct
4 Correct 51 ms 9048 KB Output is correct
5 Correct 74 ms 9308 KB Output is correct
6 Correct 72 ms 9300 KB Output is correct
7 Correct 2 ms 6232 KB Output is correct
8 Correct 20 ms 7372 KB Output is correct
9 Correct 56 ms 9304 KB Output is correct
10 Correct 59 ms 9564 KB Output is correct
11 Correct 56 ms 10304 KB Output is correct
12 Correct 81 ms 10388 KB Output is correct
13 Correct 48 ms 9052 KB Output is correct
14 Correct 52 ms 9352 KB Output is correct

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6232 KB Output is correct
2 Incorrect 2 ms 6236 KB Output isn't correct
3 Halted 0 ms 0 KB -