Submission #732205

#	Time	Username	Problem	Language	Result	Execution time	Memory
732205		anhduc2701	Power Plant (JOI20_power)	C++17	100 / 100	227 ms	49392 KiB

power

/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
*/
#include<bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define len(x) ll(x.size())
#define eb emplace_back
#define PI acos(-1.0)
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define BIT(x,i) (1&((x)>>(i)))
#define MASK(x) (1LL<<(x))
#define task "tnc"  
typedef long long ll;
typedef long double ld;
const ll INF=1e18;
const int maxn=1e6+5;
const int mod=1e9+7;
const int mo=998244353;
using pi=pair<ll,ll>;
using vi=vector<ll>;
using pii=pair<pair<ll,ll>,ll>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
string s;
int dp[maxn];
int re[maxn];
vector<int>G[maxn];
int sum[maxn];
int n;
int ans=0;
void dfs(int u,int pa){
	for(auto v:G[u]){
		if(v==pa)continue;
		dfs(v,u);
		if(s[u]=='1' && s[v]=='1'){
			ans=max(ans,2);
		}
		sum[u]+=dp[v];
	}
	dp[u]=max(s[u]-'0',sum[u]-(s[u]-'0'));
	
}
void re_dfs(int u,int pa){
	if(u!=1){
		re[u]=max(s[pa]-'0',sum[pa]-dp[u]+re[pa]-(s[pa]-'0'));
	}
	if(s[u]=='1'){
		ans=max(ans,max(1,re[u]+sum[u]-1));
	}
	else{
		ans=max(ans,re[u]+sum[u]);
	}
	for(auto v:G[u]){
		if(v==pa)continue;
		re_dfs(v,u);
	}
}
signed main()
{
	cin.tie(0),cout.tie(0)->sync_with_stdio(0);
    //freopen(task".inp" , "r" , stdin);
    //freopen(task".out" , "w" , stdout);
    cin>>n;
    for(int i=1;i<n;i++){
    	int u,v;
    	cin>>u>>v;
    	G[u].pb(v);
    	G[v].pb(u);
    }
    cin>>s;
    s=' '+s;
    dfs(1,-1);
    re_dfs(1,-1);

    cout<<ans<<"\n";
    return 0;
}

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