Submission #735778

#	Time	Username	Problem	Language	Result	Execution time	Memory
735778		alexdd	Power Plant (JOI20_power)	C++17	100 / 100	206 ms	32252 KiB

power

#include<bits/stdc++.h>
using namespace std;
const int INF = 1e9;
int n;
vector<int> con[200005];
int dp[200005][2];
bool iss[200005];
int mxm=0;
void dfs(int nod, int par)
{
    dp[nod][0]=0;
    dp[nod][1]=0;
    int sum0=0, max1=0, max0=0;
    for(auto adj:con[nod])
    {
        if(adj!=par)
        {
            dfs(adj,nod);
            sum0 += dp[adj][0];
            max1 = max(max1, dp[adj][1]);
            max0 = max(max0, dp[adj][0]);
        }
    }
    if(iss[nod])
    {
        dp[nod][0] = max(1, sum0-1);
        dp[nod][1] = max0 + 1;///dp[nod][1] = max(dp[adj][0]) + 1
    }
    else
    {
        dp[nod][0] = sum0;
        dp[nod][1] = max1;///dp[nod][1] = max(dp[adj][1])
    }
    mxm = max(mxm, dp[nod][1]);
    mxm = max(mxm, dp[nod][0]);
    //cout<<nod<<"  "<<dp[nod][0]<<" "<<dp[nod][1]<<"    "<<iss[nod]<<"\n";
}
signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);
    int a,b;
    cin>>n;
    for(int i=1;i<n;i++)
    {
        cin>>a>>b;
        con[a].push_back(b);
        con[b].push_back(a);
    }
    int cnt1=0;
    char ch;
    for(int i=1;i<=n;i++)
    {
        cin>>ch;
        if(ch=='1')
            iss[i]=1;
        else
            iss[i]=0;
        if(iss[i])
            cnt1++;
    }
    dfs(1,0);
    cout<<mxm;
    return 0;
}
/**

dp[nod][0] = scorul maxim pe care il putem obtine daca nu avem niciun nod "in-danger"
dp[nod][1] = scorul maxim pe care il putem obtine daca avem un nod "in-danger"


*/

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