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Submission #867015

# Submission time Handle Problem Language Result Execution time Memory
867015 2023-10-27T15:09:57 Z Ahmed_Solyman The Xana coup (BOI21_xanadu) C++14
50 / 100
 66 ms 21964 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;
		}
	}
	ret=1e9;
	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:86:11: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   86 |     if(c^u==0){
      |          ~^~~

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 6236 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 2 ms 6236 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 62 ms 21840 KB Output is correct
2 Correct 61 ms 21480 KB Output is correct
3 Correct 63 ms 21964 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 21844 KB Output is correct
2 Correct 64 ms 21596 KB Output is correct
3 Correct 66 ms 21844 KB Output is correct
4 Correct 51 ms 9048 KB Output is correct
5 Correct 55 ms 9304 KB Output is correct
6 Correct 56 ms 9304 KB Output is correct
7 Correct 2 ms 6232 KB Output is correct
8 Correct 19 ms 7260 KB Output is correct
9 Correct 57 ms 9316 KB Output is correct
10 Correct 60 ms 9564 KB Output is correct
11 Correct 60 ms 10332 KB Output is correct
12 Correct 58 ms 10832 KB Output is correct
13 Correct 48 ms 9048 KB Output is correct
14 Correct 52 ms 9308 KB Output is correct

Subtask #5
0 / 30.0

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