Submission #867213

#	Time	Username	Problem	Language	Result	Execution time	Memory
867213		12345678	Power Plant (JOI20_power)	C++17	0 / 100	1 ms	5168 KiB

power

#include <bits/stdc++.h>

using namespace std;

const int nx=2e5+5;
int n, u, v, dp[2][nx];
vector<int> d[nx];
string s;

void dfs(int u, int p)
{
    int cnt=0, cs=1;
    for (auto v:d[u])
    {
        if (v==p) continue;
        dfs(v, u);
        dp[0][u]+=dp[0][v];
        if (dp[0][v]!=0) cnt++;
        if (dp[1][v]>dp[1][u]) dp[1][u]=dp[1][v], cs=0; 
        if (s[u-1]&&dp[0][v]+1>=dp[1][u]) dp[1][u]=dp[0][v]+1, cs=1;
    }
    if (s[u-1]=='1') 
    {
        if (cnt>=2) dp[0][u]--;
        else dp[0][u]=1;
        if (!cs) dp[1][u]--;
    }
    //cout<<u<<' '<<dp[0][u]<<' '<<dp[1][u]<<'\n';
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=0; i<n-1; i++) cin>>u>>v, d[u].push_back(v), d[v].push_back(u);
    cin>>s;
    dfs(1, 1);
    cout<<max(dp[0][1], dp[1][1]);
}

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