oj.uz

Submission #584886

# Submission time Handle Problem Language Result Execution time Memory
584886 2022-06-28T06:16:22 Z slime Necklace (Subtask 1-3) (BOI19_necklace1) C++14
17 / 85
 120 ms 472 KB 
#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 3004;
const int MOD = 998244353;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
vector<int> prefix_function(string t) {
  int n = t.size();
  vector<int> lps(n);
  lps[0] = 0;
  for(int i=1; i<n; i++) {
    int j = lps[i-1];
    while(j > 0 && t[i] != t[j]) {
      j = lps[j-1];
    }
    if(t[i] == t[j]) lps[i] = j+1;
    else lps[i] = 0;
  }
  return lps;
}
int ans1, sst, tst;
int pows[6010];
int aa[6010], bb[6010];
const int factor = 2017;
int hasha(int l, int r) {
  int qq = aa[l-1] * pows[r - l + 1];
  qq %= MOD;
  int given = aa[r] - qq; 
  if(given < 0) given = (MOD - (abs(given) % MOD)) % MOD;
  else given %= MOD;
  return given;
}
int hashb(int l, int r) {
  int qq = bb[l-1] * pows[r - l + 1];
  qq %= MOD;
  int given = bb[r] - qq; 
  if(given < 0) given = (MOD - (abs(given) % MOD)) % MOD;
  else given %= MOD;
  return given;
}
pair<int, pair<int, int> > lcs(string a, string b) { // length, starting positions
  int n = a.size(), m = b.size();
  a = " " + a;
  b = " " + b;
  int dp[2][m+1];
  for(int i=0; i<2; i++) for(int j=0; j<=m; j++) dp[i][j] = 0;
  int ma = 0;
  for(int i=1; i<=n; i++) {
    for(int j=0; j<=m; j++) dp[i & 1][j] = 0;
    for(int j=1; j<=m; j++) {
      if(a[i] == b[j]) dp[i & 1][j] = dp[(i-1) & 1][j-1] + 1;
      else dp[i & 1][j] = 0;
      ma = max(ma, dp[i & 1][j]);
    }
  }
  aa[0] = bb[0] = 0;
  for(int i=1; i<=n; i++) aa[i] = (aa[i-1] * factor + a[i]) % MOD;
  for(int i=1; i<=m; i++) bb[i] = (bb[i-1] * factor + b[i]) % MOD;
  for(int i=1; i<=n-ma+1; i++) {
    for(int j=1; j<=m-ma+1; j++) {
      if(hasha(i, i+ma-1) == hashb(j, j+ma-1)) {
        return {ma, {i, j} };
      }
    }
  }
  assert(false);
}
void upd_ans(int new_len, int new_sst, int new_tst) {
  if(new_len > ans1) {
    ans1 = new_len;
    sst = new_sst;
    tst = new_tst;
  }
}
void out() {
  cout << ans1 << "\n";
  cout << sst - 1 << " " << tst - 1 << "\n";
}
void solve(int tc) {
  pows[0] = 1;
  for(int i=1; i<6010; i++) pows[i] = (pows[i-1] * factor) % MOD;
  string s, t;
  cin >> s >> t;
  // Need to compute answer for both t and rev(t), both s and rev(s), for all suffixes of s and t
  // Can't be more duliu

  /*
  for(int i=0; i<s.size(); i++) {
    string u;
    u += s.substr(i, s.size() - i);
    u += "?";
    u += t; // ~ 6000
    vector<int> lps = prefix_function(u);
    bool 

  }

  */

  // Compute lcs of s and t
  pair<int, pair<int, int> > res = lcs(s, t);
  upd_ans(res.first, res.second.first, res.second.second);
  // Compute lcs of s and rev(t)
  reverse(t.begin(), t.end());
  res = lcs(s, t);
  upd_ans(res.first, res.second.first, (int) t.size() - res.second.second - res.first + 2);

  reverse(t.begin(), t.end());
  out();
}
int32_t main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
// I don't know geometry.
// Teaming is unfair.

Subtask #1
5.0 / 25.0

# Verdict Execution time Memory Grader output
1 Partially correct 1 ms 340 KB Output is partially correct
2 Partially correct 1 ms 340 KB Output is partially correct
3 Partially correct 1 ms 340 KB Output is partially correct
4 Partially correct 1 ms 384 KB Output is partially correct
5 Partially correct 1 ms 340 KB Output is partially correct

Subtask #2
4.0 / 20.0

# Verdict Execution time Memory Grader output
1 Partially correct 1 ms 340 KB Output is partially correct
2 Partially correct 1 ms 340 KB Output is partially correct
3 Partially correct 1 ms 340 KB Output is partially correct
4 Partially correct 1 ms 384 KB Output is partially correct
5 Partially correct 1 ms 340 KB Output is partially correct
6 Partially correct 1 ms 376 KB Output is partially correct
7 Partially correct 1 ms 376 KB Output is partially correct
8 Partially correct 2 ms 340 KB Output is partially correct
9 Partially correct 1 ms 340 KB Output is partially correct
10 Partially correct 2 ms 340 KB Output is partially correct
11 Partially correct 2 ms 340 KB Output is partially correct
12 Partially correct 2 ms 372 KB Output is partially correct

Subtask #3
8.0 / 40.0

# Verdict Execution time Memory Grader output
1 Partially correct 1 ms 340 KB Output is partially correct
2 Partially correct 1 ms 340 KB Output is partially correct
3 Partially correct 1 ms 340 KB Output is partially correct
4 Partially correct 1 ms 384 KB Output is partially correct
5 Partially correct 1 ms 340 KB Output is partially correct
6 Partially correct 1 ms 376 KB Output is partially correct
7 Partially correct 1 ms 376 KB Output is partially correct
8 Partially correct 2 ms 340 KB Output is partially correct
9 Partially correct 1 ms 340 KB Output is partially correct
10 Partially correct 2 ms 340 KB Output is partially correct
11 Partially correct 2 ms 340 KB Output is partially correct
12 Partially correct 2 ms 372 KB Output is partially correct
13 Partially correct 29 ms 380 KB Output is partially correct
14 Partially correct 28 ms 468 KB Output is partially correct
15 Partially correct 80 ms 468 KB Output is partially correct
16 Partially correct 99 ms 468 KB Output is partially correct
17 Partially correct 120 ms 468 KB Output is partially correct
18 Partially correct 69 ms 472 KB Output is partially correct
19 Partially correct 82 ms 472 KB Output is partially correct
20 Partially correct 51 ms 472 KB Output is partially correct
21 Partially correct 59 ms 472 KB Output is partially correct