oj.uz

Submission #473750

# Submission time Handle Problem Language Result Execution time Memory
473750 2021-09-16T05:38:51 Z ntabc05101 Mag (COCI16_mag) C++11
120 / 120
 722 ms 262144 KB 
#include<bits/stdc++.h>
using namespace std;

const int MAX = 1000000;

bool cmp(const pair<int, int> &a, const pair<int, int> &b) {
  return (long long)a.first * b.second < (long long)a.second * b.first;
}

int p[MAX];
int dpup[MAX], dpdown[MAX];
vector<int> adj[MAX];
pair<int, int> res = {1e9, 1};

void dfsdown(int node, int par) {
  vector<int> L, R;
  L.push_back(0);
  for (auto &it : adj[node]) {
    if (it != par) {
      dfsdown(it, node);
      L.push_back(max(L.back(), p[it] == 1 ? dpdown[it] + 1 : 0));
    }
  }

  R.push_back(0);
  for (int i = (int)adj[node].size() - 1; i >= 0; i--) {
    int it = adj[node][i];
    if (it != par) {
      dpup[it] = (p[node] == 1 ? (1 + max(L[L.size() - R.size() - 1], R.back())): 0);
      R.push_back(max(R.back(), p[it] == 1 ? dpdown[it] + 1 : 0));
    }
  }

  dpdown[node] = L.back();
  L.clear(); R.clear();
}

void dfsup(int node, int par) {
  if (node) {
    dpup[node] = (p[par] == 1 ? max(dpup[node], 1 + dpup[par]) : 0);
  }

  pair<int, int> a = {p[node], 1};
  if (cmp(a, res)) {
    res = a;
  }
  int mx = dpup[node];

  for (auto &it : adj[node]) {
    if (it == par) {
      continue;
    }

    int val = (p[it] == 1 ? dpdown[it] + 1 : 0);
    pair<int, int> tmp = {p[node], 1 + mx + val};
    if (cmp(tmp, res)) {
      res = tmp;
    }
    mx = max(mx, val);
    dfsup(it, node);
  }
}

int main() {
  if (fopen("input.txt", "r")) {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  }

  cin.tie(0)->sync_with_stdio(0);

  int n; cin >> n;
  for (int i = 0; i < n - 1; i++) {
    int a, b; cin >> a >> b;
    a--; b--;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }

  for (int i = 0; i < n; i++) {
    cin >> p[i];
  }

  dfsdown(0, -1);
  dfsup(0, -1);

  int gc = __gcd(res.first, res.second);
  cout << res.first / gc << "/" << res.second / gc << endl;

  return 0;
}

Compilation message

mag.cpp: In function 'int main()':
mag.cpp:66:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
mag.cpp:67:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23884 KB Output is correct
2 Correct 14 ms 23756 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23828 KB Output is correct
2 Correct 16 ms 23784 KB Output is correct

Subtask #3
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 512 ms 134584 KB Output is correct

Subtask #4
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23756 KB Output is correct
2 Correct 722 ms 253188 KB Output is correct

Subtask #5
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 656 ms 248988 KB Output is correct

Subtask #6
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 647 ms 66688 KB Output is correct
2 Correct 442 ms 55720 KB Output is correct

Subtask #7
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 521 ms 71972 KB Output is correct
2 Correct 103 ms 28104 KB Output is correct
3 Correct 682 ms 262144 KB Output is correct

Subtask #8
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 105 ms 28096 KB Output is correct
2 Correct 584 ms 69244 KB Output is correct
3 Correct 527 ms 46588 KB Output is correct

Subtask #9
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 576 ms 66892 KB Output is correct
2 Correct 569 ms 66152 KB Output is correct

Subtask #10
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 560 ms 67896 KB Output is correct
2 Correct 485 ms 46924 KB Output is correct