Submission #255262

#	Time	Username	Problem	Language	Result	Execution time	Memory
255262		rama_pang	Palindromes (APIO14_palindrome)	C++14	100 / 100	81 ms	47748 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;

class Eertree {
 public:
  int sz;
  string S;
  int suff_max;
  vector<int> len;
  vector<int> occ;
  vector<int> link;
  vector<vector<int>> to;

  Eertree() : sz(2), S(), suff_max(1), len(2), occ(2), link(2), to(2, vector<int>(26, -1)) {
    len[0] = -1, link[0] = 0;
    len[1] = 0, link[1] = 0;
  }

  int NewNode() {
    len.emplace_back();
    occ.emplace_back();
    link.emplace_back();
    to.emplace_back(vector<int>(26, -1));
    return sz++;
  }

  int Add(char c) {
    S.push_back(c);
    int pos = (int) S.size() - 1;
    int cur = suff_max;
    while (pos - 1 - len[cur] < 0 || S[pos - 1 - len[cur]] != c) {
      cur = link[cur];
    }
    if (to[cur][c - 'a'] != -1) {
      suff_max = to[cur][c - 'a'];
      occ[suff_max]++;
      return 0;
    }
    suff_max = NewNode();
    occ[suff_max] = 1;
    len[suff_max] = len[cur] + 2;
    to[cur][c - 'a'] = suff_max;
    if (len[suff_max] == 1) {
      link[suff_max] = 1;
      return 1;
    }
    cur = link[cur];
    while (pos - 1 - len[cur] < 0 || S[pos - 1 - len[cur]] != c) {
      cur = link[cur];
    }
    link[suff_max] = to[cur][c - 'a'];
    return 1;
  }

  long long Solve(string S) {
    for (int i = 0; i < (int) S.size(); i++) {
      Add(S[i]);
    }
    long long ans = 0;
    for (int i = sz - 1; i > 1; i--) {
      ans = max(ans, 1ll * len[i] * occ[i]);
      occ[link[i]] += occ[i];
    }
    return ans;
  }
};

int main() {
  string S;
  cin >> S;
  cout << Eertree().Solve(S) << "\n";
  return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 27 / 27