Submission #1129259

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129259		vladilius	Power Plant (JOI20_power)	C++20	100 / 100	167 ms	32140 KiB

power

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int n; cin>>n;
    vector<int> g[n + 1];
    for (int i = 1; i < n; i++){
        int x, y; cin>>x>>y;
        g[x].pb(y);
        g[y].pb(x);
    }
    vector<bool> a(n + 1);
    for (int i = 1; i <= n; i++){
        char x; cin>>x;
        a[i] = (x == '1');
    }
    
    int dp[n + 1][2];
    function<void(int, int)> dfs = [&](int v, int pr){
        dp[v][0] = 0; dp[v][1] = a[v];
        for (int i: g[v]){
            if (i == pr) continue;
            dfs(i, v);
            dp[v][0] += max({0, dp[i][1] - 2, dp[i][0]});
            dp[v][1] = max({dp[v][1], dp[i][0] + 1, dp[i][1] - 1});
        }
        dp[v][0] = max((int) a[v], dp[v][0] - a[v]);
        if (!a[v]) dp[v][1] = 0;
    };
    dfs(1, 0);
    
    int out = 0;
    for (int i = 1; i <= n; i++){
        out = max({out, dp[i][0], dp[i][1]});
    }
    cout<<out<<"\n";
}

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