Submission #826936

#	Time	Username	Problem	Language	Result	Execution time	Memory
826936		arush_agu	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	48 ms	20652 KiB

palindromic

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;

const int p = 31;
const int m = 1e9 + 9;
vl p_pow(1e6 + 10);

void solve() {
  string s;
  cin >> s;

  int ans = 0;
  int l = 0, r = s.size() - 1;
  while (l <= r) {
    if (l == r) {
      ans++;
      break;
    }
    if (l + 1 == r) {
      ans += s[l] == s[r] ? 2 : 1;
      break;
    }

    bool f = 0;
    ll st_hash = 0, en_hash = 0;
    for (int i = 0; i <= r - l + 1; i++) {
      if (l + i >= r - i)
        break;

      st_hash += (s[l + i] - 'a' + 1) * p_pow[i];
      st_hash %= m;

      en_hash *= p;
      en_hash += (s[r - i] - 'a' + 1);
      en_hash %= m;

      if (st_hash == en_hash) {
        bool flag = 1;
        for (int j = l, k = r - i; j <= l + i; j++, k++)
          if (s[j] != s[k]) {
            flag = 0;
            break;
          }

        if (!flag)
          continue;

        ans += 2;
        l += i + 1;
        r -= i + 1;
        f = 1;
        break;
      }
    }

    if (f)
      continue;

    ans++;
    break;
  }

  cout << ans << '\n';
}

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

  clock_t start = clock();

  p_pow[0] = 1;
  for (int i = 1; i < p_pow.size(); i++)
    p_pow[i] = (p_pow[i - 1] * p) % m;

  int test_cases = 1;
  cin >> test_cases;

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:161:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  161 |   for (int i = 1; i < p_pow.size(); i++)
      |                   ~~^~~~~~~~~~~~~~
palindromic.cpp:158:11: warning: unused variable 'start' [-Wunused-variable]
  158 |   clock_t start = clock();
      |           ^~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40