Submission #623027

#	Time	Username	Problem	Language	Result	Execution time	Memory
623027		S2speed	Power Plant (JOI20_power)	C++17	100 / 100	160 ms	29832 KiB

power

#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("Ofast")

typedef long long ll;

const ll maxn = 2e5 + 17;

vector<ll> adj[maxn];
string s;
ll dp[maxn] , ans = 0;

void DFS(ll r , ll par){
	ll h = 0 , m = -1;
	for(auto i : adj[r]){
		if(i == par) continue;
		DFS(i , r);
		h += dp[i];
		m = max(m , dp[i]);
	}
	ans = max(ans , m + (s[r] == '1'));
	if(h == 0){
		dp[r] = (s[r] == '1');
	} else {
		dp[r] = max((ll)(s[r] == '1') , h - (s[r] == '1'));
	}
	ans = max(ans , dp[r]);
	return;
}

int main(){
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);

	ll n;
	cin>>n;
	for(ll i = 1 ; i < n ; i++){
		ll v , u;
		cin>>v>>u; v--; u--;
		adj[v].push_back(u); adj[u].push_back(v);
	}
	cin>>s;
	DFS(0 , -1);
	cout<<ans<<'\n';
	return 0;
}

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