oj.uz

Submission #48358

# Submission time Handle Problem Language Result Execution time Memory
48358 2018-05-11T20:01:43 Z octopuses Palindromes (APIO14_palindrome) C++17
58 / 100
 1000 ms 63496 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;

char tmp[N];
int n;
ll answer, ans;
int Suf[N][20], c[N], d[N], temp[N], cnt[N];
int A[N], B[N];
int P[N], C[N];
int L[N], R[N], F[N];
string a;
vector < int > G[N];
vector < pair < int, int > > g[N];

inline int get(int x)
{
  int 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;
  C[v] += C[u];
  P[u] = v;
  ans = max(ans, C[v] * 1ll);
}

inline int fnd(int mn, int v, int u)
{
  int s = 0;
  for(int k = 18; k >= 0; -- k)
    if(Suf[u][k] == Suf[v][k])
    {
      u += (1 << k);
      v += (1 << k);
      s += (1 << k);
    }
  return min(s, mn);
}

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] <= (1 << (k - 1)))
        continue;
      int j = d[i] - (1 << (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] + (1 << (k - 1)) > n + 1) || Suf[c[i] + (1 << (k - 1))][k - 1] != Suf[c[i - 1] + (1 << (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()
{
  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, C[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;
  for(int k = n / 2 + 1; k >= 1; -- k)
  {
    for(int i = 0; i < G[k].size(); ++ i)
    {
      int v = G[k][i];
      int x = get(c[v]);
      if(x != 0)
        g[fnd(k, d[x], v)].push_back({d[x], v});
      int y = R[x];
      R[x] = c[v];
      L[c[v]] = x;
      if(y != n + 1)
        g[fnd(k, d[y], v)].push_back({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, C[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)
    {
      int v = G[k][i];
      int x = get(c[v]);
      if(x != 0)
        g[fnd(k, d[x], v)].push_back({d[x], v});
      int y = R[x];
      R[x] = c[v];
      L[c[v]] = x;
      if(y != n + 1)
        g[fnd(k, d[y], v)].push_back({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:173:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < G[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:189:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < g[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:204:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < G[k].size(); ++ i)
                    ~~^~~~~~~~~~~~~
palindrome.cpp:219:22: 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 13 ms 14456 KB Output is correct
3 Correct 13 ms 14616 KB Output is correct
4 Correct 13 ms 14616 KB Output is correct
5 Correct 12 ms 14744 KB Output is correct
6 Correct 12 ms 14744 KB Output is correct
7 Correct 12 ms 14744 KB Output is correct
8 Correct 12 ms 14744 KB Output is correct
9 Correct 12 ms 14780 KB Output is correct
10 Correct 12 ms 14780 KB Output is correct
11 Correct 12 ms 14780 KB Output is correct
12 Correct 11 ms 14780 KB Output is correct
13 Correct 12 ms 14780 KB Output is correct
14 Correct 12 ms 14780 KB Output is correct
15 Correct 12 ms 14780 KB Output is correct
16 Correct 12 ms 14780 KB Output is correct
17 Correct 12 ms 14780 KB Output is correct
18 Correct 12 ms 14780 KB Output is correct
19 Correct 12 ms 14780 KB Output is correct
20 Correct 16 ms 14780 KB Output is correct
21 Correct 12 ms 14780 KB Output is correct
22 Correct 12 ms 14780 KB Output is correct
23 Correct 12 ms 14780 KB Output is correct
24 Correct 16 ms 14780 KB Output is correct
25 Correct 13 ms 14780 KB Output is correct
26 Correct 13 ms 14780 KB Output is correct
27 Correct 12 ms 14780 KB Output is correct
28 Correct 12 ms 14780 KB Output is correct
29 Correct 12 ms 14780 KB Output is correct
30 Correct 12 ms 14780 KB Output is correct
31 Correct 13 ms 14780 KB Output is correct
32 Correct 12 ms 14780 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 15 ms 14844 KB Output is correct
3 Correct 13 ms 14844 KB Output is correct
4 Correct 13 ms 14848 KB Output is correct
5 Correct 13 ms 14972 KB Output is correct
6 Correct 14 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 14 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 14 ms 14972 KB Output isn't correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 16380 KB Output is correct
2 Correct 19 ms 16380 KB Output is correct
3 Correct 21 ms 16380 KB Output is correct
4 Correct 21 ms 16380 KB Output is correct
5 Correct 20 ms 16380 KB Output is correct
6 Correct 20 ms 16380 KB Output is correct
7 Correct 19 ms 16380 KB Output is correct
8 Correct 19 ms 16380 KB Output is correct
9 Correct 20 ms 16384 KB Output is correct
10 Correct 22 ms 16384 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 30836 KB Output is correct
2 Correct 99 ms 30836 KB Output is correct
3 Correct 101 ms 30836 KB Output is correct
4 Correct 112 ms 30836 KB Output is correct
5 Correct 126 ms 30836 KB Output is correct
6 Correct 108 ms 30836 KB Output is correct
7 Correct 110 ms 30836 KB Output is correct
8 Correct 142 ms 30836 KB Output is correct
9 Correct 122 ms 30836 KB Output is correct
10 Correct 145 ms 30836 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 389 ms 63496 KB Output is correct
2 Correct 359 ms 63496 KB Output is correct
3 Correct 353 ms 63496 KB Output is correct
4 Correct 427 ms 63496 KB Output is correct
5 Correct 976 ms 63496 KB Output is correct
6 Correct 449 ms 63496 KB Output is correct
7 Correct 460 ms 63496 KB Output is correct
8 Execution timed out 1088 ms 63496 KB Time limit exceeded
9 Halted 0 ms 0 KB -