Submission #868676

#	Time	Username	Problem	Language	Result	Execution time	Memory
868676		sleepntsheep	Power Plant (JOI20_power)	C++17	0 / 100	1 ms	6492 KiB

power

#include <cstdio>
#include <cstring>
#include <cassert>
#include <string>
#include <deque>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <iostream>
#include <utility>
using namespace std;
using ll = long long;
using ld = long double;
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false)

#define N 200005
#define ALL(x) x.begin(), x.end()

int n, ans, f[N], h[N], pwr[N];
vector<int> g[N];
char s[N];

void dfs(int u, int p)
{
    if (s[u]=='1')++pwr[u], f[u]=1;
    int C=0,F=0;
    for (auto v : g[u]) if (v^p) 
    {
        dfs(v, u);
        pwr[u] += pwr[v];
        C+=!!pwr[v];
        F+=f[v];
    }
    if (s[u]=='1')
    {
        f[u]=max(F-(C>1), 1);
    }
    else f[u]=max(f[u],F);
}

void dfs2(int u, int p)
{
    int sib=h[u];
    for (auto v:g[u])if (v^p)
    {
        sib+=f[v];
    }
    if(s[u]=='1') sib=max(sib-1,1);
    if(s[u]=='1')h[u]=max(h[u],1);
    for (auto v : g[u]) if (v^p)
    {
        if (s[v]=='1')h[v]=1;
        h[v]=max(h[v],sib-f[v]);
        dfs2(v, u);
    }
}

void dfs3(int u, int p)
{
    ans=max(ans, f[u]+h[p]);
    for(auto v:g[u]) if(v-p)dfs3(v,u);
}

int main()
{
    ShinLena;
    cin >> n;
    for (int i = 1, u, v; i < n; ++i) cin >> u >> v, g[u].push_back(v), g[v].push_back(u);
    cin >> (s+1);
    dfs(1, 0);
    dfs2(1,0);
    dfs3(1,0);
    //for(int i=1;i<=n;++i) cerr<<f[i]<< ' '<<h[i]<<endl;
    cout<<ans;

    return 0;
}

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