Submission #332632

#	Time	Username	Problem	Language	Result	Execution time	Memory
332632		YJU	Power Plant (JOI20_power)	C++14	47 / 100	1569 ms	34988 KiB

power

#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=4e5+5;
const ll K=350;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()

ll n,x,y,h[N],dp[N],ans,col[N],sum;
vector<ll> v[N];
string s;

void DFS(ll nd,ll pa){
	dp[nd]=0;
	for(auto i:v[nd]){
		if(i==pa)continue;
		DFS(i,nd);
		dp[nd]+=dp[i];
	}
	dp[nd]=max(dp[nd]-col[nd],col[nd]);
	return ;
}

void move(ll rt,ll to){
	dp[rt]=0;
	for(auto i:v[rt]){
		if(i==to)continue;
		dp[rt]+=dp[i];
	}
	dp[rt]=max(dp[rt]-col[rt],col[rt]);
	dp[to]=0;
	for(auto i:v[to]){
		dp[to]+=dp[i];
	}
	dp[to]=max(dp[to]-col[to],col[to]);
}

void reroot(ll nd,ll pa){
	ans=max(ans,dp[nd]);
	for(auto i:v[nd]){
		if(i==pa)continue;
		move(nd,i);
		reroot(i,nd);
		move(i,nd);
	}
}

int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	cin>>n;
	REP(i,n-1)cin>>x>>y,v[x].pb(y),v[y].pb(x);
	cin>>s;
	REP(i,n)if(s[i]=='1')col[i+1]=1,++sum;
	if(sum>=2)ans=2;else ans=sum;
	DFS(1,0);
	reroot(1,0);
	cout<<ans<<"\n";
	return 0;
}

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 0 / 53