oj.uz

Submission #48362

# Submission time Handle Problem Language Result Execution time Memory
48362 2018-05-11T20:26:11 Z octopuses Palindromes (APIO14_palindrome) C++17
58 / 100
 1000 ms 56864 KB 
#include <bits/stdc++.h>
#pragma GCC optimize("O3")

#define ll long long
#define fr first
#define sc second
#define M (ll)(3e17)
#define MAX(a,b) (a>b?a:b)

using namespace std;
const int N = 300020;

int n;
ll answer, ans;
int Suf[N][20], c[N], d[N], cnt[N], T[20];
int A[N], B[N];
int P[N];
int L[N], R[N], F[N];
string a;
vector < int > G[N];
vector < pair < int, int > > g[N];
int S, X, Y;

inline int get(int x)
{
  S = 0;
  while(x > 0)
  {
    S = MAX(S, F[x]);
    x -= x & (-x);
  }
  return S;
}
inline void upd(int x, int v)
{
  while(x <= n)
  {
    F[x] = MAX(F[x], v);
    x += x & (-x);
  }
}

int Parent(int v)
{
  if(P[v] == v)
    return v;
  return P[v] = Parent(P[v]);
}

inline void DSU(int v, int u)
{
  v = Parent(v);
  u = Parent(u);
  if(v == u)
    return;
  cnt[v] += cnt[u];
  P[u] = v;
  ans = MAX(ans, cnt[v] * 1ll);
}

inline void fnd(int mn, int v, int u)
{
  S = 0, X = v, Y = u;
  for(int k = 18; k >= 0; -- k)
    if(Suf[u][k] == Suf[v][k])
    {
      u += T[k];
      v += T[k];
      S += T[k];
    }
  if(S >= mn)
    DSU(X, Y);
  else
    g[S].push_back({X, Y});
}

void sufsort()
{
  Suf[n + 1][0] = 0;
  int tot = 1;
  for(char ch = 'a'; ch <= 'z'; ++ ch)
    for(int i = 1; i <= n; ++ i)
      if(a[i] == ch)
        d[tot ++] = i;
  tot = 0;
  for(int i = 1; i <= n; ++ i)
  {
    if(a[d[i]] != a[d[i - 1]])
      tot ++;
    Suf[d[i]][0] = tot;
  }
  d[0] = n + 1;
  for(int i = 0; i <= n; ++ i)
    c[i] = d[i];
  for(int k = 1; k < 19; ++ k)
  {
    for(int i = 0; i <= n; ++ i)
      cnt[i] = 0;
    for(int i = 1; i <= n + 1; ++ i)
      cnt[Suf[i][k - 1]] ++;
    for(int i = 1; i <= n; ++ i)
      cnt[i] += cnt[i - 1];
    for(int i = n; i >= 0; -- i)
    {
      if(d[i] <= T[k - 1])
        continue;
      int j = d[i] - T[k - 1];
      c[cnt[Suf[j][k - 1]] - 1] = j;
      cnt[Suf[j][k - 1]] --;
    }
    tot = 0;
    Suf[n + 1][k] = 0;
    for(int i = 1; i <= n; ++ i)
    {
      d[i] = c[i];
      if(Suf[c[i]][k - 1] != Suf[c[i - 1]][k - 1] || (c[i - 1] + T[k - 1] > n + 1) || Suf[c[i] + T[k - 1]][k - 1] != Suf[c[i - 1] + T[k - 1]][k - 1])
        tot ++;
      Suf[c[i]][k] = tot;
    }
  }
  for(int i = 1; i <= n; ++ i)
    c[d[i]] = i;
}

void palindrome()
{
  A[1] = 1;
  int r = 1;
  int l = 1;
  for(int i = 2; i <= n; ++ i)
  {
    A[i] = 1;
    if(r >= i)
      A[i] = min(A[l + r - i], r - i + 1);
    while(i + A[i] <= n && i - A[i] > 0 && a[i - A[i]] == a[i + A[i]])
      A[i] ++;
    if(i + A[i] - 1 > r)
      r = i + A[i] - 1, l = i - A[i] + 1;
  }
  B[1] = 0;
  l = r = 1;
  for(int i = 1; i <= n; ++ i)
  {
    B[i] = 0;
    if(r >= i)
      B[i] = min(B[l + r - i + 1], r - i + 1);
    while(i + B[i] <= n && i - B[i] - 1 > 0 && a[i + B[i]] == a[i - B[i] - 1])
      B[i] ++;
    if(i + B[i] - 1 > r)
      r = i + B[i] - 1, l = i - B[i];
  }
}

int main()
{
  for(int i = 0; i < 19; ++ i)
    T[i] = (1 << i);
  char tmp;
  a = '#';
  tmp = getchar();
  while(tmp <= 'z' && tmp >= 'a')
    a += tmp, tmp = getchar(), n ++;
  a += char('a' - 1);
  sufsort();
  palindrome();

// Odd Palindromes

  for(int i = 1; i <= n; ++ i)
    P[i] = i, cnt[i] = 1;
  for(int i = 1; i <= n; ++ i)
    G[A[i]].push_back(i);
  ans = 0;
  R[0] = n + 1;
  L[n + 1] = 0;
  int v, x, y;
  for(int k = n / 2 + 1; k >= 1; -- k)
  {
    for(int i = 0; i < G[k].size(); ++ i)
    {
      v = G[k][i];
      x = get(c[v]);
      if(x != 0)
        fnd(k, d[x], v);
      y = R[x];
      R[x] = c[v];
      L[c[v]] = x;
      if(y != n + 1)
        fnd(k, d[y], v);
      R[c[v]] = y;
      L[y] = c[v];
      upd(c[v], c[v]);
      ans = MAX(ans, 1ll);
    }
    for(int i = 0; i < g[k].size(); ++ i)
      DSU(g[k][i].first, g[k][i].second);
    answer = MAX(answer, ans * (2 * k - 1ll));
  }

//  Even Palindromes

  for(int i = 1; i <= n; ++ i)
    P[i] = i, cnt[i] = 1, G[i].clear(), g[i].clear(), F[i] = 0;
  for(int i = 1; i <= n; ++ i)
    G[B[i]].push_back(i);
  ans = 0;
  L[n + 1] = 0; R[0] = n + 1; F[0] = 0;
  for(int k = n / 2; k >= 1; -- k)
  {
    for(int i = 0; i < G[k].size(); ++ i)
    {
      v = G[k][i];
      x = get(c[v]);
      if(x != 0)
        fnd(k, d[x], v);
      y = R[x];
      R[x] = c[v];
      L[c[v]] = x;
      if(y != n + 1)
        fnd(k, d[y], v);
      R[c[v]] = y;
      L[y] = c[v];
      upd(c[v], c[v]);
    }
    for(int i = 0; i < g[k].size(); ++ i)
      DSU(g[k][i].first, g[k][i].second);
    answer = MAX(answer, ans * (2ll * k));
  }
  printf("%lld\n", answer);
}

Compilation message

palindrome.cpp: In function 'int main()':
palindrome.cpp:179:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < G[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:195:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < g[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:210:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < G[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:225:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < g[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 14456 KB Output is correct
2 Correct 12 ms 14456 KB Output is correct
3 Correct 12 ms 14492 KB Output is correct
4 Correct 12 ms 14492 KB Output is correct
5 Correct 12 ms 14536 KB Output is correct
6 Correct 12 ms 14544 KB Output is correct
7 Correct 13 ms 14564 KB Output is correct
8 Correct 12 ms 14624 KB Output is correct
9 Correct 12 ms 14752 KB Output is correct
10 Correct 12 ms 14752 KB Output is correct
11 Correct 12 ms 14752 KB Output is correct
12 Correct 12 ms 14752 KB Output is correct
13 Correct 12 ms 14752 KB Output is correct
14 Correct 13 ms 14752 KB Output is correct
15 Correct 12 ms 14752 KB Output is correct
16 Correct 12 ms 14752 KB Output is correct
17 Correct 16 ms 14752 KB Output is correct
18 Correct 13 ms 14752 KB Output is correct
19 Correct 12 ms 14752 KB Output is correct
20 Correct 12 ms 14752 KB Output is correct
21 Correct 16 ms 14752 KB Output is correct
22 Correct 16 ms 14752 KB Output is correct
23 Correct 12 ms 14752 KB Output is correct
24 Correct 12 ms 14752 KB Output is correct
25 Correct 13 ms 14752 KB Output is correct
26 Correct 15 ms 14752 KB Output is correct
27 Correct 12 ms 14752 KB Output is correct
28 Correct 13 ms 14752 KB Output is correct
29 Correct 15 ms 14752 KB Output is correct
30 Correct 12 ms 14752 KB Output is correct
31 Correct 13 ms 14752 KB Output is correct
32 Correct 13 ms 14752 KB Output is correct

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 14844 KB Output is correct
2 Correct 13 ms 14844 KB Output is correct
3 Correct 14 ms 14972 KB Output is correct
4 Correct 13 ms 14972 KB Output is correct
5 Correct 13 ms 14972 KB Output is correct
6 Correct 13 ms 14972 KB Output is correct
7 Correct 13 ms 14972 KB Output is correct
8 Correct 13 ms 14972 KB Output is correct
9 Correct 13 ms 14972 KB Output is correct
10 Correct 13 ms 14972 KB Output is correct
11 Correct 13 ms 14972 KB Output is correct
12 Incorrect 13 ms 14972 KB Output isn't correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 16252 KB Output is correct
2 Correct 18 ms 16252 KB Output is correct
3 Correct 20 ms 16252 KB Output is correct
4 Correct 20 ms 16252 KB Output is correct
5 Correct 20 ms 16252 KB Output is correct
6 Correct 20 ms 16252 KB Output is correct
7 Correct 19 ms 16252 KB Output is correct
8 Correct 20 ms 16252 KB Output is correct
9 Correct 20 ms 16252 KB Output is correct
10 Correct 22 ms 16252 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 82 ms 28916 KB Output is correct
2 Correct 91 ms 28916 KB Output is correct
3 Correct 89 ms 28916 KB Output is correct
4 Correct 115 ms 28916 KB Output is correct
5 Correct 121 ms 28916 KB Output is correct
6 Correct 102 ms 28916 KB Output is correct
7 Correct 105 ms 28916 KB Output is correct
8 Correct 136 ms 28916 KB Output is correct
9 Correct 108 ms 28916 KB Output is correct
10 Correct 143 ms 28916 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 339 ms 56864 KB Output is correct
2 Correct 403 ms 56864 KB Output is correct
3 Correct 348 ms 56864 KB Output is correct
4 Correct 410 ms 56864 KB Output is correct
5 Correct 928 ms 56864 KB Output is correct
6 Correct 445 ms 56864 KB Output is correct
7 Correct 465 ms 56864 KB Output is correct
8 Execution timed out 1002 ms 56864 KB Time limit exceeded
9 Halted 0 ms 0 KB -