Submission #355557

#	Time	Username	Problem	Language	Result	Execution time	Memory
355557		Lam_lai_cuoc_doi	Power Plant (JOI20_power)	C++17	100 / 100	193 ms	27032 KiB

power

#include <iostream>
#include <cstdio>
#include <vector>
#define task ""
using namespace std;
using ll = long long;
using ld = long double;

const int N = 2e5 + 2;
const int Inf = 1e9 + 7;
vector<int> adj[N];
int n, dp[N][2], root;
bool vis[N];
string s;

void Read()
{
    cin >> n;
    for (int i = 1; i < n; ++i)
    {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    cin >> s;
    s = " " + s;
}

void dfs(int v)
{
    dp[v][0] = dp[v][1] = s[v] - '0';
    int sum(0);
    for (auto i : adj[v])
        if (dp[i][0] == -Inf)
        {
            dfs(i);
            sum += dp[i][1];
            dp[v][0] = max(dp[v][0], dp[i][0]);
            if (s[v] == '1')
                dp[v][0] = max(dp[v][0], dp[i][1] + (s[v] - '0'));
        }
    dp[v][1] = max(dp[v][1], sum - (s[v] - '0'));
    dp[v][0] = max(dp[v][0], sum - (s[v] - '0'));
}

int GetAns(int v)
{
    fill_n(&dp[0][0], N * 2, -Inf);
    root = v;
    dfs(v);
    return dp[v][0];
}

void Solve()
{
    cout << GetAns(1);
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }
    Read();
    Solve();
}

Compilation message (stderr)

power.cpp: In function 'int32_t main()':
power.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   67 |         freopen(task ".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   68 |         freopen(task ".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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