Submission #493636

#	Time	Username	Problem	Language	Result	Execution time	Memory
493636		600Mihnea	Power Plant (JOI20_power)	C++17	0 / 100	4 ms	5068 KiB

power

#include <bits/stdc++.h>

using namespace std;

const int N = (int) 2e5 + 7;
int n;
int sol;
int dp[N];
int is[N];
vector<int> g[N];
string s;

void build(int a, int p = -1) {
  dp[a] = 0;
  for (auto &b : g[a]) {
    if (b != p) {
      build(b, a);
      dp[a] += dp[b];
    }
  }
  dp[a] -= is[a];
  dp[a] = max(dp[a], is[a]);
}
int main() {
  ios::sync_with_stdio(0); cin.tie(0);

  freopen ("input.txt", "r", stdin);

  cin >> n;
  for (int i = 1; i < n; i++) {
    int a, b;
    cin >> a >> b;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  cin >> s;
  int cnt = 0;
  for (int i = 1; i <= n; i++) {
    is[i] = s[i - 1] - '0';
    cnt += is[i];
  }
  sol = min(cnt, 2);
  for (int i = 1; i <= n; i++) {
    build(i);
    sol = max(sol, dp[i]);
  }
  cout << sol << "\n";

  return 0;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:27:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |   freopen ("input.txt", "r", stdin);
      |   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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