Submission #782324

#	Time	Username	Problem	Language	Result	Execution time	Memory
782324		tvladm2009	Power Plant (JOI20_power)	C++17	100 / 100	143 ms	24080 KiB

power

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

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

void compute(int a, int p = 0) {
  dp[a] = 0;
  for (auto &b : g[a]) {
    if (b != p) {
      dp[a] += max(dp[b], is[b]);
    }
  }
  dp[a] -= is[a];
}

void dfs(int a, int p = 0) {
  for (auto &b : g[a]) {
    if (b != p) {
      dfs(b, a);
    }
  }
  compute(a, p);
}

void rer(int p, int a) {
  dp[a] -= max(dp[p], is[p]);
  dp[p] += max(dp[a], is[a]);
}

void solve(int a, int p = 0) {
  sol = max(sol, dp[a]);
  for (auto &b : g[a]) {
    if (b != p) {
      rer(b, a);
      solve(b, a);
      rer(a, b);
    }
  }
}

signed main() {
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

  ///freopen("input", "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);
  dfs(1);
  solve(1);
  cout << sol << "\n";
  return 0;
}

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