oj.uz

Submission #331577

# Submission time Handle Problem Language Result Execution time Memory
331577 2020-11-29T03:07:27 Z quindecim Islands (IOI08_islands) C++17
90 / 100
 693 ms 131076 KB 
#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MOD = 1e9+7;
const int MX = 1e6+10;
const ll INF = 0x3f3f3f3f3f3f3f3f;

int n, m, a[MX], w[MX];
vector<int> adj[MX];
ll ans, ret;
vector<ll> V, S;
bool vv[MX];

inline int cycle(int u) {
  if(vv[u]) return u;
  vv[u] = 1;
  int r = cycle(a[u]);
  if(r) {
    V.push_back(u);
    S.push_back(w[u]);
    if(r==u) return 0;
    else return r;
  }
  vv[u] = 0;
  return 0;
}

inline ll dfs(int u) {
  ll mx = 0;
  vv[u] = 1;
  for(int v : adj[u]) {
    if(!vv[v]) {
      ll r = dfs(v) + w[v];
      ret = max(ret, mx+r);
      mx = max(mx, r);
    }
  }
  return mx;
}

void solve(int u) {
  V.clear(); S.clear();
  cycle(u);
  reverse(V.begin(), V.end());
  reverse(S.begin(), S.end());
  for(auto &v : V) v = dfs(v);
  m = V.size();
  for(int i = m-1; i > 0; --i) swap(S[i], S[i-1]);
  for(int i = 1; i < m; ++i) S[i] += S[i-1];
  ll m1 = -INF, m2 = -INF;
  for(int i = 0; i < m; ++i) {
    ret = max(ret, max(m1+S[i]+V[i], m2-S[i]+V[i]+S[m-1]));
    m1 = max(m1, V[i]-S[i]);
    m2 = max(m2, V[i]+S[i]);
  }
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin >> n;
  for(int i = 1; i <= n; ++i) {
    cin >> a[i] >> w[i];
    adj[a[i]].push_back(i);
  }
  for(int i = 1; i <= n; ++i)
    if(!vv[i]) solve(i), ans+=ret, ret = 0;
  cout << ans << "\n";
  return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23788 KB Output is correct
2 Correct 18 ms 23788 KB Output is correct
3 Correct 18 ms 23916 KB Output is correct
4 Correct 17 ms 23788 KB Output is correct
5 Correct 18 ms 23788 KB Output is correct
6 Correct 18 ms 23788 KB Output is correct
7 Correct 18 ms 23788 KB Output is correct
8 Correct 18 ms 23788 KB Output is correct
9 Correct 17 ms 23788 KB Output is correct
10 Correct 18 ms 23788 KB Output is correct
11 Correct 18 ms 23788 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23916 KB Output is correct
2 Correct 18 ms 23916 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 23916 KB Output is correct
2 Correct 19 ms 24172 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 24708 KB Output is correct
2 Correct 31 ms 26348 KB Output is correct
3 Correct 25 ms 24812 KB Output is correct
4 Correct 21 ms 24300 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 27496 KB Output is correct
2 Correct 49 ms 29548 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 79 ms 32108 KB Output is correct
2 Correct 83 ms 39824 KB Output is correct
3 Correct 109 ms 44552 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 128 ms 38380 KB Output is correct
2 Correct 166 ms 53628 KB Output is correct
3 Correct 186 ms 69328 KB Output is correct
4 Correct 233 ms 74752 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 256 ms 38748 KB Output is correct
2 Correct 534 ms 90236 KB Output is correct
3 Correct 239 ms 49132 KB Output is correct
4 Correct 311 ms 77520 KB Output is correct
5 Correct 315 ms 75264 KB Output is correct
6 Correct 693 ms 53868 KB Output is correct
7 Correct 354 ms 102728 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 372 ms 130796 KB Output is correct
2 Correct 345 ms 97772 KB Output is correct
3 Runtime error 343 ms 131076 KB Execution killed with signal 9 (could be triggered by violating memory limits)
4 Halted 0 ms 0 KB -