Problem p02589 (C++) — buggy submission, verdict: Time Limit Exceeded

/*input
6
b
a
abc
c
d
ab
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_set;
#pragma GCC optimize("unroll-loops,no-stack-protector")
// order_of_key #of elements less than x
//  find_by_order kth element
typedef long long int ll;
#define ld double
#define pii pair<ll, ll>
#define f first
#define s second
#define pb push_back
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REP1(i, n) for (int i = 1; i <= n; i++)
#define FILL(n, x) memset(n, x, sizeof(n))
#define ALL(_a) _a.begin(), _a.end()
#define sz(x) (int)x.size()
const ll maxn = 2e5 + 5;
const ll maxlg = __lg(maxn) + 2;
const ll INF64 = 4e18;
const int INF = 0x3f3f3f3f;
const ll MOD = 3006703054056749LL;
const ld PI = 3.14159265358979323846;
const ld eps = 1e-9;
#define lowb(x) x & (-x)
#define MNTO(x, y) x = min(x, (__typeof__(x))y)
#define MXTO(x, y) x = max(x, (__typeof__(x))y)
#define SORT_UNIQUE(c)                                                         \\
  (sort(c.begin(), c.end()),                                                   \\
   c.resize(distance(c.begin(), unique(c.begin(), c.end()))))
#define GET_POS(c, x) (lower_bound(c.begin(), c.end(), x) - c.begin())
#define MP make_pair
ll mult(ll a, ll b) {
  ll res = 0LL;
  while (b) {
    if (b & 1)
      res = (res + a) % MOD;
    a = (a + a) % MOD;
    b >>= 1;
  }
  return res % MOD;
}
ll mypow(ll a, ll b) {
  ll res = 1LL;
  while (b) {
    if (b & 1)
      res = res * a % MOD;
    a = a * a % MOD;
    b >>= 1;
  }
  return res;
}
string arr[maxn];
map<ll, int> mp;
int cnt[26];
int32_t main() {
  ios::sync_with_stdio(false), cin.tie(0);
  int n;
  cin >> n;
  ll ans = 0;
  REP(i, n) {
    cin >> arr[i];
    string s = arr[i];
    reverse(ALL(s));
    ll hsh = 0;
    REP(j, sz(s)) {
      hsh = (hsh * 27LL + (s[j] - 'a' + 1));
      if (hsh >= MOD)
        hsh %= MOD;
    }
    mp[hsh]++;
  }
  REP(i, n) {
    string s = arr[i];
    REP(j, sz(s)) cnt[s[j] - 'a']++;
    ll hsh = 0;
    for (int j = sz(s) - 1; j >= 0; j--) {
      REP(k, 26) {
        if (cnt[k]) {
          ll x = (hsh * 27LL + k + 1);
          if (x >= MOD)
            x %= MOD;
          if (mp.count(x))
            ans += mp[x];
        }
      }
      cnt[s[j] - 'a']--;
      hsh = (hsh * 27LL + (s[j] - 'a' + 1));
      if (hsh >= MOD)
        hsh %= MOD;
    }
    REP(j, 26) cnt[j] = 0;
  }
  cout << ans - n;
}


Error: TLE

Fixed submission:

/*input
6
b
a
abc
c
d
ab
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_set;
#pragma GCC optimize("unroll-loops,no-stack-protector")
// order_of_key #of elements less than x
//  find_by_order kth element
typedef long long int ll;
#define ld double
#define pii pair<ll, ll>
#define f first
#define s second
#define pb push_back
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REP1(i, n) for (int i = 1; i <= n; i++)
#define FILL(n, x) memset(n, x, sizeof(n))
#define ALL(_a) _a.begin(), _a.end()
#define sz(x) (int)x.size()
const ll maxn = 2e5 + 5;
const ll maxlg = __lg(maxn) + 2;
const ll INF64 = 4e18;
const int INF = 0x3f3f3f3f;
const ll MOD = 3006703054056749LL;
const ld PI = 3.14159265358979323846;
const ld eps = 1e-9;
#define lowb(x) x & (-x)
#define MNTO(x, y) x = min(x, (__typeof__(x))y)
#define MXTO(x, y) x = max(x, (__typeof__(x))y)
#define SORT_UNIQUE(c)                                                         \\
  (sort(c.begin(), c.end()),                                                   \\
   c.resize(distance(c.begin(), unique(c.begin(), c.end()))))
#define GET_POS(c, x) (lower_bound(c.begin(), c.end(), x) - c.begin())
#define MP make_pair
ll mult(ll a, ll b) {
  ll res = 0LL;
  while (b) {
    if (b & 1)
      res = (res + a) % MOD;
    a = (a + a) % MOD;
    b >>= 1;
  }
  return res % MOD;
}
ll mypow(ll a, ll b) {
  ll res = 1LL;
  while (b) {
    if (b & 1)
      res = res * a % MOD;
    a = a * a % MOD;
    b >>= 1;
  }
  return res;
}
string arr[maxn];
unordered_map<ll, int> mp;
int cnt[26];
int32_t main() {
  ios::sync_with_stdio(false), cin.tie(0);
  mp.reserve(32768);
  mp.max_load_factor(0.25);
  int n;
  cin >> n;
  ll ans = 0;
  ll inv = (mypow(26, MOD - 2));
  REP(i, n) {
    cin >> arr[i];
    string s = arr[i];
    reverse(ALL(s));
    ll hsh = 0;
    REP(j, sz(s)) {
      hsh = (hsh * 27LL + (s[j] - 'a' + 1));
      if (hsh >= MOD)
        hsh %= MOD;
    }
    mp[hsh]++;
  }
  REP(i, n) {
    string s = arr[i];
    REP(j, sz(s)) cnt[s[j] - 'a']++;
    ll hsh = 0;
    for (int j = sz(s) - 1; j >= 0; j--) {
      REP(k, 26) {
        if (cnt[k]) {
          ans += mp[(hsh * 27LL + k + 1) % MOD];
        }
      }
      cnt[s[j] - 'a']--;
      hsh = (hsh * 27LL + (s[j] - 'a' + 1));
      if (hsh >= MOD)
        hsh %= MOD;
    }
    REP(j, 26) cnt[j] = 0;
  }
  cout << ans - n;
}