Submission #1251518

#	Time	Username	Problem	Language	Result	Execution time	Memory
1251518		CrabCNH	Power Plant (JOI20_power)	C++20	100 / 100	75 ms	28228 KiB

power

#include <bits/stdc++.h>

#define task     "BriantheCrab"

#define int    long long
#define pii    pair <int, int>
#define fi     first
#define se     second
#define szf    sizeof
#define sz(s)  (int)((s).size())
#define all(v) (v).begin(), (v).end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using namespace std;

template <class T> void minimize (T &t, T f) {if (t > f) t = f;}
template <class T> void maximize (T &t, T f) {if (t < f) t = f;}

const int maxN = 2e5 + 5;
const int inf = 1e18 + 7;
const int mod = 1e9 + 7;

// khong tu code thi khong kha len duoc dau

int n;
int a[maxN];
int dp[maxN];
vector <int> adj[maxN];
int res = 0;

void dfs (int u, int p) {
    int mx = 0;
    for (auto v : adj[u]) {
        if (v == p) {
            continue;
        }
        dfs (v, u);
        dp[u] += dp[v];
        maximize (mx, dp[v] + a[u]);
    }
    maximize (res, mx);
    //cout << sum << ' ' << dp[u] << '\n';
    if (a[u]) {
        dp[u] = max (dp[u] - 1, 1LL);
    }
    return;
}

void solve () {
    cin >> n;
    for (int i = 1; i <= n - 1; i ++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back (v);
        adj[v].push_back (u);
    }
    
    for (int i = 1; i <= n; i ++) {
        char c;
        cin >> c;
        a[i] = (c == '1');
    }
    dfs (1, 1);
    // for (int i = 1; i <= n; i ++) {
        // cout << "bruh " << i << ' ' << dp[i] << '\n';
    // }
    cout << max (*max_element (dp + 1, dp + n + 1), res);
    return;
}

signed main () {
    cin.tie (nullptr) -> sync_with_stdio (false);
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    int t = 1;
    //cin >> t;
    while (t --) {
        solve ();
    } 
    return 0;
}
// thfv

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:77:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:78:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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