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Submission #807566

# Submission time Handle Problem Language Result Execution time Memory
807566 2023-08-04T19:30:59 Z peijar Palindromes (APIO14_palindrome) C++17
100 / 100
 53 ms 65288 KB 
#include <bits/stdc++.h>
using namespace std;

string to_string(string s) { return s; }
template <typename T> string to_string(T v) {
  bool first = true;
  string res = "[";
  for (const auto &x : v) {
    if (!first)
      res += ", ";
    first = false;
    res += to_string(x);
  }
  res += "]";
  return res;
}

void dbg_out() { cout << endl; }
template <typename Head, typename... Tail> void dbg_out(Head H, Tail... T) {
  cout << ' ' << to_string(H);
  dbg_out(T...);
}

#ifdef DEBUG
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

const int MAX_TRA = 26; // number of transitions
int normalize(char c) { // normalize `c` in [0, ..., MAX_TRA-1]
  return c - 'a';
}

struct PalindromicTree {
  // len = length of the palindrome, sufCount = number of suffix palindrome
  // link = node of the maximum suffix palindrome, occAsMax = used in computeOcc
  struct Node {
    int len, link, sufCount, occAsMax, occ;
    array<int, MAX_TRA> next;
    Node() : occAsMax(0), occ(0) { next.fill(-1); }
  };

  string s;
  vector<Node> t; // tree. node 0: root with len -1, node 1: root with len 0
  int suff;       // node of the current maximum suffix palindrome

  PalindromicTree() {
    suff = 1;
    t.resize(2);
    t[0].len = -1;
    t[0].link = 0;
    t[0].sufCount = 0;
    t[1].len = 0;
    t[1].link = 0;
    t[1].sufCount = 0;
  }

  int suffix(int x, int i) {
    while (i - t[x].len - 1 < 0 || s[i - t[x].len - 1] != s[i])
      x = t[x].link;
    return x;
  }

  // returns true if `c` created a new distinct palindrome
  bool add(char c) {
    int let = normalize(c);
    int pos = s.size();
    s.push_back(c);
    suff = suffix(suff, pos);

    bool newNode = t[suff].next[let] == -1;
    if (newNode) {
      int x = t.size();
      t[suff].next[let] = x;
      dbg(x);
      t.emplace_back();
      t[x].len = t[suff].len + 2;
      t[x].link = suff == 0 ? 1 : t[suffix(t[suff].link, pos)].next[let];
      t[x].sufCount = 1 + t[t[x].link].sufCount;
    }
    int x = t[suff].next[let];
    ++t[x].occAsMax;
    suff = x;
    return newNode;
  }

  void getOcc() {
    for (int i = (int)t.size() - 1; i >= 0; --i) {
      t[i].occ += t[i].occAsMax;
      t[t[i].link].occ += t[i].occ;
    }
    t[0].occ = t[1].occ = 0;
  }
};

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

  string s;
  cin >> s;
  PalindromicTree tree;
  for (char c : s)
    tree.add(c);
  tree.getOcc();

  long long sol = 0;
  for (int i = 2; i < (int)tree.t.size(); ++i) {
    int len = tree.t[i].len;
    int occ = tree.t[i].occ;
    dbg(len, occ);
    sol = max(sol, len * 1LL * occ);
  }
  cout << sol << endl;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 316 KB Output is correct
16 Correct 0 ms 316 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Correct 0 ms 340 KB Output is correct
22 Correct 0 ms 340 KB Output is correct
23 Correct 0 ms 340 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 0 ms 340 KB Output is correct
26 Correct 0 ms 340 KB Output is correct
27 Correct 0 ms 340 KB Output is correct
28 Correct 0 ms 340 KB Output is correct
29 Correct 0 ms 340 KB Output is correct
30 Correct 0 ms 224 KB Output is correct
31 Correct 0 ms 340 KB Output is correct
32 Correct 1 ms 316 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 468 KB Output is correct
2 Correct 1 ms 468 KB Output is correct
3 Correct 1 ms 468 KB Output is correct
4 Correct 1 ms 444 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2420 KB Output is correct
2 Correct 2 ms 2420 KB Output is correct
3 Correct 1 ms 2408 KB Output is correct
4 Correct 2 ms 2408 KB Output is correct
5 Correct 2 ms 2420 KB Output is correct
6 Correct 2 ms 2420 KB Output is correct
7 Correct 2 ms 2456 KB Output is correct
8 Correct 1 ms 324 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 1384 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 16636 KB Output is correct
2 Correct 12 ms 16600 KB Output is correct
3 Correct 11 ms 16592 KB Output is correct
4 Correct 11 ms 16636 KB Output is correct
5 Correct 17 ms 16624 KB Output is correct
6 Correct 10 ms 16624 KB Output is correct
7 Correct 11 ms 16648 KB Output is correct
8 Correct 2 ms 852 KB Output is correct
9 Correct 4 ms 4864 KB Output is correct
10 Correct 10 ms 16668 KB Output is correct

Subtask #5
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 65280 KB Output is correct
2 Correct 51 ms 65236 KB Output is correct
3 Correct 49 ms 65200 KB Output is correct
4 Correct 49 ms 65260 KB Output is correct
5 Correct 47 ms 65220 KB Output is correct
6 Correct 53 ms 65288 KB Output is correct
7 Correct 32 ms 33096 KB Output is correct
8 Correct 5 ms 1756 KB Output is correct
9 Correct 5 ms 1756 KB Output is correct
10 Correct 31 ms 33152 KB Output is correct
11 Correct 43 ms 65208 KB Output is correct
12 Correct 8 ms 5312 KB Output is correct