Submission #390152

#	Time	Username	Problem	Language	Result	Execution time	Memory
390152		Alex_tz307	Traffic (IOI10_traffic)	C++17	50 / 100	578 ms	174644 KiB

traffic

#include <bits/stdc++.h>

using namespace std;

void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
}

const int NMAX = 1e6;
int a[NMAX], dp[NMAX], sum[NMAX], ans;
vector<int> G[NMAX];

void dfs1(int u, int parent) {
  sum[u] = a[u];
  for (int v : G[u])
    if (v != parent) {
      dfs1(v, u);
      sum[u] += sum[v];
      if (sum[v] > dp[u])
        dp[u] = sum[v];
    }
}

void dfs2(int u, int parent, int s) {
  if (dp[u] < dp[ans])
    ans = u;
  for (int v : G[u])
    if (v != parent) {
      int aux = dp[v];
      if (s + a[u] > dp[v])
        dp[v] = s + a[u];
      dfs2(v, u, s + a[u]);
      dp[v] = aux;
    }
}

int LocateCentre(int N, int pp[], int S[], int D[]) {
  for (int i = 0; i < N - 1; ++i) {
    G[S[i]].emplace_back(D[i]);
    G[D[i]].emplace_back(S[i]);
  }
  for (int i = 0; i < N; ++i)
    a[i] = pp[i];
  dfs1(0, -1);
  dfs2(0, -1, 0);
  return ans;
}

/*int N, P[NMAX], S[NMAX], D[NMAX];

int main() {
  fastIO();
  cin >> N;
  for (int i = 0; i < N; ++i)
    cin >> P[i];
  for (int i = 0; i < N - 1; ++i)
    cin >> S[i] >> D[i];
  cout << LocateCentre(N, P, S, D) << '\n';
  return 0;
} */

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25