Submission #1250755

#	Time	Username	Problem	Language	Result	Execution time	Memory
1250755		wedonttalkanymore	Power Plant (JOI20_power)	C++20	100 / 100	106 ms	27072 KiB

power

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 2e5 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 1 << 16;

int n;
vector <int> adj[N];
int dp[N];
string s;
int ans = 0;

void dfs(int u, int par) {
    // dp[u] = (s[u] == '1');
    int maxx = 0, sum = 0;
    for (auto v : adj[u]) {
        if (v == par) continue;
        dfs(v, u);
        maxx = max(maxx, dp[v]);
        sum += dp[v];
    }
    dp[u] = sum;
    // cout << u << ' ' << sum << ' ' << maxx << '\n';
    if (s[u] == '1') dp[u] = max(dp[u] - 1, 1LL); // sum la tong dp cua cac con
    ans = max({ans, dp[u], maxx + (s[u] == '1')}); // chon them con u
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    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;
    dfs(1, 0);
    // for (int i = 1; i <= n; i++) cout << dp[i] << ' ';
    // cout << '\n';
    cout << ans;
    return 0;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
power.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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