Submission #582703

#	Time	Username	Problem	Language	Result	Execution time	Memory
582703		Theo830	Power Plant (JOI20_power)	C++17	100 / 100	213 ms	33896 KiB

power

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define ull unsigned ll
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
ll dp[200005][2];
vector<vll>adj;
string s;
ll solve(ll idx,ll par,bool ep){
    if(dp[idx][ep] != -1){
        return dp[idx][ep];
    }
    ll ans = s[idx - 1] - '0';
    if(ep){
        ll res = -ans;
        for(auto x:adj[idx]){
            if(x != par){
                res += solve(x,idx,ep);
            }
        }
        ans = max(ans,res);
    }
    else{
        ans = 0;
        for(auto x:adj[idx]){
            if(x != par){
                ans = max(ans,solve(x,idx,0));
            }
        }
        if(s[idx - 1] == '1'){
            ll res = 1;
            for(auto x:adj[idx]){
                if(x != par){
                    res = max(res,1 + solve(x,idx,1));
                }
            }
            ans = max(ans,res);
        }
        ll res = -(s[idx - 1] - '0');
        for(auto x:adj[idx]){
            if(x != par){
                res += solve(x,idx,1);
            }
        }
        ans = max(ans,res);
    }
    return dp[idx][ep] = ans;
}
int main(void){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll n;
    cin>>n;
    memset(dp,-1,sizeof dp);
    adj.assign(n+5,vll());
    f(i,0,n-1){
        ll a,b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    cin>>s;
    cout<<solve(1,0,0)<<"\n";
}

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