oj.uz

Submission #403272

# Submission time Handle Problem Language Result Execution time Memory
403272 2021-05-13T01:10:25 Z rama_pang Necklace (Subtask 1-3) (BOI19_necklace1) C++17
85 / 85
 313 ms 452 KB 
#include <bits/stdc++.h>
using namespace std;

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

  string S, T;
  cin >> S >> T;

  const auto GetLink = [&](string s) {
    vector<int> link(s.size() + 1, 0);
    for (int i = 1, j = 0; i < int(s.size()); i++) {
      while (j > 0 && !(j < int(s.size()) && s[i] == s[j])) {
        j = link[j];
      }
      if (j < int(s.size()) && s[i] == s[j]) {
        j += 1;
      }
      link[i + 1] = j;
    }
    return link;
  };

  const auto Solve = [&]() -> array<int, 3> {
    int N = S.size();
    int M = T.size();

    array<int, 3> ans = {0, 0, 0};

    vector<int> lcs(M); // lcs[t] = longest common suffix of S[0...s], T[0...t]
    for (int s = 0; s < N; s++) {
      for (int t = M - 1; t >= 0; t--) {
        if (S[s] == T[t]) {
          lcs[t] = 1 +  (t > 0 ? lcs[t - 1] : 0);
        } else {
          lcs[t] = 0;
        }
      }

      vector<int> dp(M); // dp[t] = longest prefix of S[s+1...N] which is suffix of T[0...t]

      string str;
      for (int i = s + 1; i < N; i++) {
        str.push_back(S[i]);
      }

      vector<int> link = GetLink(str);
      for (int t = 0, i = 0; t < M; t++) {
        while (i > 0 && !(i < int(str.size()) && T[t] == str[i])) {
          i = link[i];
        }
        if (i < int(str.size()) && T[t] == str[i]) {
          i += 1;
        }
        dp[t] = max(dp[t], i);
      }
      for (int t = M - 2; t >= 0; t--) {
        dp[t] = max(dp[t], dp[t + 1] - 1);
      }

      for (int t = 0; t < M; t++) if (lcs[t] > 0) {
        int k = lcs[t] + (t < lcs[t] ? 0 : dp[t - lcs[t]]);
        ans = max(ans, {k, s - lcs[t] + 1, t - k + 1});
      }
    }

    return ans;
  };

  auto ans1 = Solve();
  reverse(begin(T), end(T));
  auto ans2 = Solve();
  ans2[2] = int(T.size()) - ans2[2] - ans2[0];
  auto ans = max(ans1, ans2);

  cout << ans[0] << '\n' << ans[1] << ' ' << ans[2] << '\n';
  return 0;
}

Subtask #1
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 7 ms 332 KB Output is correct
7 Correct 8 ms 344 KB Output is correct
8 Correct 6 ms 332 KB Output is correct
9 Correct 6 ms 332 KB Output is correct
10 Correct 6 ms 332 KB Output is correct
11 Correct 6 ms 332 KB Output is correct
12 Correct 6 ms 332 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 7 ms 332 KB Output is correct
7 Correct 8 ms 344 KB Output is correct
8 Correct 6 ms 332 KB Output is correct
9 Correct 6 ms 332 KB Output is correct
10 Correct 6 ms 332 KB Output is correct
11 Correct 6 ms 332 KB Output is correct
12 Correct 6 ms 332 KB Output is correct
13 Correct 313 ms 356 KB Output is correct
14 Correct 271 ms 364 KB Output is correct
15 Correct 312 ms 380 KB Output is correct
16 Correct 289 ms 452 KB Output is correct
17 Correct 236 ms 368 KB Output is correct
18 Correct 250 ms 380 KB Output is correct
19 Correct 266 ms 452 KB Output is correct
20 Correct 285 ms 352 KB Output is correct
21 Correct 278 ms 384 KB Output is correct