oj.uz

Submission #259195

# Submission time Handle Problem Language Result Execution time Memory
259195 2020-08-07T11:03:22 Z EntityIT Palindromes (APIO14_palindrome) C++14
100 / 100
 454 ms 18752 KB 
#include <bits/stdc++.h>
using namespace std;

#define ALL(x) (x).begin(), (x).end()
#define SZ(x) static_cast<int>((x).size())

template<class T, size_t D>
struct vec : vector<vec<T, D - 1>> {
  template<class... Args>
  vec(size_t n = 0, Args... args)
      : vector<vec<T, D - 1>>(n, vec<T, D - 1>(args...)) {}
};
template<class T>
struct vec<T, 1> : vector<T> {
  template<class... Args>
  vec(Args... args)
      : vector<T>(args...) {}
};

template<class T>
inline bool Minimize(T& a, const T& b) { return a > b ? a = b, true : false; }
template<class T>
inline bool Maximize(T& a, const T& b) { return a < b ? a = b, true : false; }
inline int Next(int i, int n) { return i == n - 1 ? 0 : i + 1; }
inline int Prev(int i, int n) { return !i ? n - 1 : i - 1; }

mt19937 rng(static_cast<uint32_t>(chrono::steady_clock::now().time_since_epoch().count()));

vec<pair<int, int>, 1> Manacher(const string& s) {
  vec<pair<int, int>, 1> max_palindromes(SZ(s));

  for (int i = 0, l = -1, r = -1; i < SZ(s); ++i) {
    if (i > r) {
      for (l = i - 1, r = i; ~l && r < SZ(s) && s[l] == s[r]; --l, ++r);
      max_palindromes[i].first = r - i; ++l; --r;
    } else {
      if (max_palindromes[l + r - (i - 1)].first < r - i + 1) {
        max_palindromes[i].first = max_palindromes[l + r - (i - 1)].first;
      } else {
        for (++r, l = (i << 1) - 1 - r; ~l && r < SZ(s) && s[l] == s[r]; --l, ++r);
        max_palindromes[i].first = r - i; ++l; --r;
      }
    }
  }

  for (int i = 0, l = -1, r = -1; i < SZ(s); ++i) {
    if (i > r) {
      for (l = i - 1, r = i + 1; ~l && r < SZ(s) && s[l] == s[r]; --l, ++r);
      max_palindromes[i].second = r - i; ++l; --r;
    } else {
      if (max_palindromes[l + r - i].second < r - i + 1) {
        max_palindromes[i].second = max_palindromes[l + r - i].second;
      } else {
        for (++r, l = (i << 1) - r; ~l && r < SZ(s) && s[l] == s[r]; --l, ++r);
        max_palindromes[i].second = r - i; ++l; --r;
      }
    }
  }

  return max_palindromes;
}

struct SuffixArray {
  vec<int, 1> ordered_suffixes, ranks, lcps;
  SuffixArray(const string& s) {
    int n = SZ(s);

    ordered_suffixes = vec<int, 1>(n); iota(ALL(ordered_suffixes), 0);
    sort(ALL(ordered_suffixes), [&](int i, int j) {
      return s[i] < s[j];
    });
    ranks = vec<int, 1>(n);
    for (int i = 1; i < n; ++i) {
      ranks[ordered_suffixes[i]] = ranks[ordered_suffixes[i - 1]] + (s[ordered_suffixes[i - 1]] < s[ordered_suffixes[i]]);
    }

    vec<int, 1> counters(n), next_ordered_suffixes(n), next_ranks(n);
    for (int i = 1; ranks[ordered_suffixes.back()] < n - 1; i <<= 1) {
      for (int j = 0; j < n; ++j) {
        counters[ranks[ordered_suffixes[j]]] = j;
      }
      for (int j = n - 1; ~j; --j) {
        if (ordered_suffixes[j] >= i) {
          next_ordered_suffixes[counters[ranks[ordered_suffixes[j] - i]]--] = ordered_suffixes[j] - i;
        }
      }
      for (int j = n - i; j < n; ++j) {
        next_ordered_suffixes[counters[ranks[j]]--] = j;
      }
      ordered_suffixes.swap(next_ordered_suffixes);

      next_ranks[ordered_suffixes[0]] = 0;
      for (int j = 1; j < n; ++j) {
        next_ranks[ordered_suffixes[j]] = next_ranks[ordered_suffixes[j - 1]] + (ranks[ordered_suffixes[j - 1]] != ranks[ordered_suffixes[j]] || ordered_suffixes[j - 1] + i >= n || ranks[ordered_suffixes[j - 1] + i] != ranks[ordered_suffixes[j] + i]);
      }
      ranks.swap(next_ranks);
    }

    lcps = vec<int, 1>(n - 1);
    for (int i = 0, j = 0; i < n; ++i, j = max(j - 1, 0)) {
      if (ranks[i] < n - 1) {
        for (int k = ordered_suffixes[ranks[i] + 1]; max(k, i) + j < n && s[k + j] == s[i + j]; ++j);
        lcps[ranks[i]] = j;
      }
    }
  }
};

struct DSU {
  int n_sets;
  vec<int, 1> parents, cardinalities;
  DSU(int t_n_sets)
    : n_sets(t_n_sets),
      parents(n_sets),
      cardinalities(n_sets, 1) {
    iota(ALL(parents), 0);
  }

  int Parent(int i) {
    return i == parents[i] ? i : parents[i] = Parent(parents[i]);
  }
  bool SameSet(int i, int j) {
    return Parent(i) == Parent(j);
  }
  bool Unite(int i, int j) {
    i = Parent(i); j = Parent(j);
    if (i == j) {
      return false;
    }
    if (cardinalities[i] > cardinalities[j]) {
      swap(i, j);
    }
    --n_sets;
    parents[i] = j;
    cardinalities[j] += cardinalities[i];
    return true;
  }
};

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

  string s; cin >> s;

  auto max_palindromes = Manacher(s);

  SuffixArray sa(s);

  int64_t answer = 0;

  for (int i = SZ(s) >> 1; i; --i) {
    static vec<int, 1> ordered_positions;
    static auto ordered_position = ordered_positions.begin();
    if (!SZ(ordered_positions)) {
      ordered_positions = vec<int, 1>(SZ(s));
      ordered_position = ordered_positions.begin();
      iota(ALL(ordered_positions), 0);
      sort(ALL(ordered_positions), [&](const auto& x, const auto& y) {
        return max_palindromes[sa.ordered_suffixes[x]].first > max_palindromes[sa.ordered_suffixes[y]].first;
      });
    }

    static vec<int, 1> ordered_links;
    static auto ordered_link = ordered_links.begin();
    if (!SZ(ordered_links)) {
      ordered_links = vec<int, 1>(SZ(s) - 1);
      ordered_link = ordered_links.begin();
      iota(ALL(ordered_links), 0);
      sort(ALL(ordered_links), [&](const auto& x, const auto& y) {
        return sa.lcps[x] > sa.lcps[y];
      });
    }

    static DSU dsu(SZ(s));

    static vec<int, 1> values(SZ(s));
    static int max_value = 0;

    for (; ordered_link != ordered_links.end() && sa.lcps[*ordered_link] >= i; ++ordered_link) {
      int u = dsu.Parent(*ordered_link), v = dsu.Parent((*ordered_link) + 1);
      dsu.Unite(u, v);
      Maximize(max_value, (values[dsu.Parent(u)] += values[u ^ v ^ dsu.Parent(u)]));
    }

    for (; ordered_position != ordered_positions.end() && max_palindromes[sa.ordered_suffixes[*ordered_position]].first >= i; ++ordered_position) {
      int u = dsu.Parent(*ordered_position);
      Maximize(max_value, (++values[u]));
    }

    Maximize(answer, static_cast<int64_t>(max_value) * (i << 1));
  }

  for (int i = (SZ(s) + 1) >> 1; i; --i) {
    static vec<int, 1> ordered_positions;
    static auto ordered_position = ordered_positions.begin();
    if (!SZ(ordered_positions)) {
      ordered_positions = vec<int, 1>(SZ(s));
      ordered_position = ordered_positions.begin();
      iota(ALL(ordered_positions), 0);
      sort(ALL(ordered_positions), [&](const auto& x, const auto& y) {
        return max_palindromes[sa.ordered_suffixes[x]].second > max_palindromes[sa.ordered_suffixes[y]].second;
      });
    }

    static vec<int, 1> ordered_links;
    static auto ordered_link = ordered_links.begin();
    if (!SZ(ordered_links)) {
      ordered_links = vec<int, 1>(SZ(s) - 1);
      ordered_link = ordered_links.begin();
      iota(ALL(ordered_links), 0);
      sort(ALL(ordered_links), [&](const auto& x, const auto& y) {
        return sa.lcps[x] > sa.lcps[y];
      });
    }

    static DSU dsu(SZ(s));

    static vec<int, 1> values(SZ(s));
    static int max_value = 0;

    for (; ordered_link != ordered_links.end() && sa.lcps[*ordered_link] >= i; ++ordered_link) {
      int u = dsu.Parent(*ordered_link), v = dsu.Parent((*ordered_link) + 1);
      dsu.Unite(u, v);
      Maximize(max_value, (values[dsu.Parent(u)] += values[u ^ v ^ dsu.Parent(u)]));
    }

    for (; ordered_position != ordered_positions.end() && max_palindromes[sa.ordered_suffixes[*ordered_position]].second >= i; ++ordered_position) {
      int u = dsu.Parent(*ordered_position);
      Maximize(max_value, (++values[u]));
    }

    Maximize(answer, static_cast<int64_t>(max_value) * ((i << 1) - 1));
  }

  cout << answer << '\n';

  return 0;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 0 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 1 ms 384 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 0 ms 384 KB Output is correct
16 Correct 0 ms 384 KB Output is correct
17 Correct 0 ms 384 KB Output is correct
18 Correct 0 ms 384 KB Output is correct
19 Correct 0 ms 384 KB Output is correct
20 Correct 0 ms 384 KB Output is correct
21 Correct 0 ms 384 KB Output is correct
22 Correct 0 ms 384 KB Output is correct
23 Correct 0 ms 384 KB Output is correct
24 Correct 0 ms 384 KB Output is correct
25 Correct 0 ms 384 KB Output is correct
26 Correct 1 ms 384 KB Output is correct
27 Correct 0 ms 384 KB Output is correct
28 Correct 0 ms 384 KB Output is correct
29 Correct 0 ms 384 KB Output is correct
30 Correct 0 ms 384 KB Output is correct
31 Correct 0 ms 384 KB Output is correct
32 Correct 0 ms 384 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 1 ms 384 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 896 KB Output is correct
2 Correct 6 ms 896 KB Output is correct
3 Correct 7 ms 896 KB Output is correct
4 Correct 6 ms 896 KB Output is correct
5 Correct 7 ms 896 KB Output is correct
6 Correct 7 ms 896 KB Output is correct
7 Correct 6 ms 896 KB Output is correct
8 Correct 4 ms 896 KB Output is correct
9 Correct 4 ms 896 KB Output is correct
10 Correct 6 ms 896 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 80 ms 6648 KB Output is correct
2 Correct 64 ms 6496 KB Output is correct
3 Correct 81 ms 6624 KB Output is correct
4 Correct 77 ms 6624 KB Output is correct
5 Correct 115 ms 6496 KB Output is correct
6 Correct 97 ms 6528 KB Output is correct
7 Correct 75 ms 6496 KB Output is correct
8 Correct 40 ms 6496 KB Output is correct
9 Correct 87 ms 6624 KB Output is correct
10 Correct 112 ms 6496 KB Output is correct

Subtask #5
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 277 ms 18492 KB Output is correct
2 Correct 187 ms 18496 KB Output is correct
3 Correct 262 ms 18496 KB Output is correct
4 Correct 221 ms 18496 KB Output is correct
5 Correct 454 ms 18496 KB Output is correct
6 Correct 283 ms 18628 KB Output is correct
7 Correct 266 ms 18620 KB Output is correct
8 Correct 140 ms 18500 KB Output is correct
9 Correct 142 ms 18496 KB Output is correct
10 Correct 439 ms 18632 KB Output is correct
11 Correct 220 ms 18508 KB Output is correct
12 Correct 354 ms 18752 KB Output is correct