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Submission #867012

# Submission time Handle Problem Language Result Execution time Memory
867012 2023-10-27T15:08:25 Z Ahmed_Solyman The Xana coup (BOI21_xanadu) C++14
50 / 100
 97 ms 20216 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(0){
		ret=0;
		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);
    //f///reopen("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){
      |          ~^~~
xanadu.cpp:54:7: warning: variable 'flag' set but not used [-Wunused-but-set-variable]
   54 |  bool flag=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 97 ms 20216 KB Output is correct
2 Correct 90 ms 20136 KB Output is correct
3 Correct 92 ms 20192 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 82 ms 20164 KB Output is correct
2 Correct 88 ms 20032 KB Output is correct
3 Correct 65 ms 20216 KB Output is correct
4 Correct 54 ms 9048 KB Output is correct
5 Correct 76 ms 9364 KB Output is correct
6 Correct 62 ms 9308 KB Output is correct
7 Correct 2 ms 6232 KB Output is correct
8 Correct 27 ms 7272 KB Output is correct
9 Correct 83 ms 9296 KB Output is correct
10 Correct 95 ms 9556 KB Output is correct
11 Correct 88 ms 10124 KB Output is correct
12 Correct 63 ms 10296 KB Output is correct
13 Correct 79 ms 9044 KB Output is correct
14 Correct 60 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 -