제출 #1311768

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1311768		thelegendary08	The Xana coup (BOI21_xanadu)	C++17	0 / 100	39 ms	20700 KiB

xanadu

#include<bits/stdc++.h>
// #include<atcoder/modint>
// #include<atcoder/convolution>
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define F first
#define S second
#define rs resize
#define ft front()
#define bk back()
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define r0f(i,n) for(int i = n-1; i >= 0; i--)
#define R0F(i,k,n) for(int i = n-1; i >= k; i--)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define SUM(v) (accumulate(all(v), 0LL))
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define pout(a) cout<<a.first<<' '<<a.second<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<endl
#define dout(a) cout<<a<<' '<<#a<<endl
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<endl
#define YN(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
#define yn(x); if(x){cout<<"Yes"<<'\n';}else{cout<<"No"<<'\n';}
#define p2(x) (1LL << (x))
#define pct(x) (__builtin_popcountll((x)))
#define ist(x,y) (((x) >> (y)) & 1)
template<class T, class U> bool ckmin(T& a, const U& b) { return (T)b < a ? a = (T)b, 1 : 0; } 
template<class T, class U> bool ckmax(T& a, const U& b) { return a < (T)b ? a = (T)b, 1 : 0; } 
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
// using namespace atcoder; 
// using mint = modint998244353;
// using mint = modint1000000007;
const int mxn = 1e5 + 5; 
// mint fact[mxn], inv[mxn];
// mint C(int n, int r){return fact[n] * inv[n-r] * inv[r];}
// mint snb(int n, int r){return C(n + r, n);}
vi adj[mxn]; int col[mxn], dp[mxn][2][2];
void dfs(int node, int from){
	for(auto u : adj[node])if(u!=from){
		dfs(u,node);
	}
	f0r(x,2){
		col[node] ^= x; 
		f0r(y,2){ //y=1 means take x = 0 for children, otherwise take x = 1
			int dif = 1e9, sum = 0, xo = col[node] ^ y; bool ok = 1; for(auto u : adj[node])if(u!=from){
				if(dp[u][y][0] == 1e9 && dp[u][y][1] == 1e9)ok=0;
				else if(dp[u][y][0] < dp[u][y][1])sum += dp[u][y][0]; 
				else sum += dp[u][y][1], xo ^= 1; 
				if(dp[u][y][0] != 1e9 && dp[u][y^1][1] != 1e9)ckmin(dif, abs(dp[u][y][0]-dp[u][y][1]));
			} 
			if(!ok)continue;
			if(xo==0)dp[node][x][y] = sum + y; 
			else if(dif == 1e9)continue;
			else dp[node][x][y] = sum + dif + y; 
		}
		col[node] ^= x; 
	}
}
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	//ifstream cin(".in");
	//ofstream cout(".out");
	// fact[0]=1;FOR(i,1,mxn)fact[i]=fact[i-1]*i;inv[mxn-1]=fact[mxn-1].inv();r0f(i,mxn-1)inv[i]=inv[i+1]*(i+1);
	int n; cin>>n; f0r(i,n-1){in2(a,b);a--;b--;adj[a].pb(b);adj[b].pb(a);} f0r(i,n)cin>>col[i]; f0r(i,n)f0r(j,2)f0r(k,2)dp[i][j][k]=1e9;
	dfs(0,-1); int ans = min(dp[0][0][0],dp[0][0][1]); if(ans==1e9)out("impossible"); else out(ans);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30