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

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
// #pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64

#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
// #define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v)                                                         \\
  REP(i, v.size()) cout << v[i] << " \\n"[i == (int)v.size() - 1]
template <typename T1, typename T2> inline void chmin(T1 &a, T2 b) {
  if (a > b)
    a = b;
}
template <typename T1, typename T2> inline void chmax(T1 &a, T2 b) {
  if (a < b)
    a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;
// int dx[4] = { 0,0,-1,1 }, dy[4] = { 1,-1,0,0 };

struct Trie {
  bool f;
  bool isend;
  int siz[26];
  int cnt;
  int ch;
  Trie *par;
  Trie *next[26];
  Trie() : cnt(0) {
    REP(i, 26) siz[i] = 0;
    isend = false;
    f = 0;
    par = (Trie *)0;
    fill(next, next + 26, (Trie *)0);
  }
};
Trie *ins(string t, Trie *r) {
  for (int i = 0; i < t.size(); i++) {
    int c = t[i] - 'a';
    if (!r->next[c])
      r->next[c] = new Trie;
    r->next[c]->par = r;
    r = r->next[c];
    r->f = 1;
    r->cnt++;
    r->ch = c;
    if (i == (int)t.size() - 1)
      r->isend = true;
  }
  return r;
}
void dfs(Trie *r, int c) {
  if (r->ch == c) {
    r->siz[c] = r->cnt;
    REP(i, 26) {
      if (r->next[i]) {
        Trie *nr = r->next[i];
        // nr->siz[i] += nr->cnt;
        dfs(nr, c);
        // r->siz[c] += nr->siz[c];
      }
    }
  } else {
    REP(i, 26) {
      if (r->next[i]) {
        Trie *nr = r->next[i];
        // nr->siz[i] += nr->cnt;
        dfs(nr, c);
        r->siz[c] += nr->siz[c];
      }
    }
  }
}
void dfs(Trie *r) {
  REP(i, 26) {
    if (r->next[i]) {
      Trie *nr = r->next[i];
      dfs(nr);
    }
  }
  REP(i, 26) {
    if (r->ch == i) {
      r->siz[i] = r->cnt;
    } else {
      REP(j, 26) {
        if (r->next[j]) {
          r->siz[i] += r->next[j]->siz[i];
        }
      }
    }
  }
  // if (r->ch == c) {
  //	r->siz[c] = r->cnt;
  //	REP(i, 26) {
  //		if (r->next[i]) {
  //			Trie *nr = r->next[i];
  //			//nr->siz[i] += nr->cnt;
  //			dfs(nr, c);
  //			//r->siz[c] += nr->siz[c];
  //		}
  //	}
  // }
  // else {
  //	REP(i, 26) {
  //		if (r->next[i]) {
  //			Trie *nr = r->next[i];
  //			//nr->siz[i] += nr->cnt;
  //			dfs(nr, c);
  //			r->siz[c] += nr->siz[c];
  //		}
  //	}
  // }
}
void show(Trie *r, string &s) {
  cerr << s << endl;
  REP(i, 26) {
    if (r->next[i]) {
      s += (char)(i + 'a');
      show(r->next[i], s);
      s.pop_back();
    }
  }
}
void solve() {
  // map<pair<string, char>, int>mp;
  int N;
  cin >> N;
  vector<string> v(N);
  REP(i, N) {
    cin >> v[i];
    VREVERSE(v[i]);
  }
  Trie *r = new Trie;
  vector<Trie *> ts;
  Trie *zero = 0;
  REP(i, N) {
    ins(v[i], r);
    while (r->par != zero)
      r = r->par;
  }
  // print("a");
  while (r->par != zero)
    r = r->par;
  REP(c, 26) {
    dfs(r, c);
    while (r->par != zero)
      r = r->par;
  }
  // print("b");
  while (r->par != zero)
    r = r->par;
  ll ans = 0;
  string t;
  // show(r, t);
  REP(i, N) {
    // DEBUG(v[i]);
    // show(r, v[i]);
    int n = v[i].size();
    REP(j, n - 1) r = r->next[v[i][j] - 'a'];
    // ans += r->siz[v[i][n - 1] - 'a'] - 1;
    ll res = 0;
    REP(c, 26) {
      if (r->next[c]) {
        res += r->next[c]->siz[v[i][n - 1] - 'a'];
      }
    }
    res--;
    while (r->par != zero)
      r = r->par;
    // DEBUG(res);
    ans += res;
  }
  print(ans);
}

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  // int q;
  // cin >> q;
  // while (q--)
  solve();
}


Error: TLE

Fixed submission:

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("unroll-loops")
// #pragma warning(disable : 4996)

#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcount __popcnt
#define __builtin_popcountll __popcnt64

#endif

#include <limits.h>
#include <math.h>
#include <time.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m - 1; i >= n; --i)
#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v, n) reverse(v, v + n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define print(x) cout << (x) << '\\n'
#define pe(x) cout << (x) << " "
#define DEBUG(x) cout << #x << ": " << x << endl
#define lb(v, n) lower_bound(v.begin(), v.end(), (n))
#define ub(v, n) upper_bound(v.begin(), v.end(), (n))
#define int long long
// #define double long double
#define all(x) (x).begin(), (x).end()
#define print_space(v)                                                         \\
  REP(i, v.size()) cout << v[i] << " \\n"[i == (int)v.size() - 1]
template <typename T1, typename T2> inline void chmin(T1 &a, T2 b) {
  if (a > b)
    a = b;
}
template <typename T1, typename T2> inline void chmax(T1 &a, T2 b) {
  if (a < b)
    a = b;
}
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
std::random_device rd;
std::mt19937 mt(rd());
constexpr ll MOD = 1e9 + 7;
constexpr int MAX = 500050;
const double pi = acos(-1);
constexpr double EPS = 1e-8;
constexpr ll LINF = 1e18 + 1;
constexpr int INF = 1e9 + 1;
// int dx[4] = { 0,0,-1,1 }, dy[4] = { 1,-1,0,0 };

struct Trie {
  bool f;
  bool isend;
  vector<int> siz;
  int cnt;
  int ch;
  Trie *par;
  Trie *next[26];
  Trie() : siz(26, 0), cnt(0) {
    isend = false;
    f = 0;
    par = (Trie *)0;
    fill(next, next + 26, (Trie *)0);
  }
};
Trie *ins(string t, Trie *r) {
  for (int i = 0; i < t.size(); i++) {
    int c = t[i] - 'a';
    if (!r->next[c])
      r->next[c] = new Trie;
    r->next[c]->par = r;
    r = r->next[c];
    r->f = 1;
    r->cnt++;
    r->ch = c;
    if (i == (int)t.size() - 1)
      r->isend = true;
  }
  return r;
}
void dfs(Trie *r, int c) {
  if (r->ch == c) {
    r->siz[c] = r->cnt;
    REP(i, 26) {
      if (r->next[i]) {
        Trie *nr = r->next[i];
        // nr->siz[i] += nr->cnt;
        dfs(nr, c);
        // r->siz[c] += nr->siz[c];
      }
    }
  } else {
    REP(i, 26) {
      if (r->next[i]) {
        Trie *nr = r->next[i];
        // nr->siz[i] += nr->cnt;
        dfs(nr, c);
        r->siz[c] += nr->siz[c];
      }
    }
  }
}
void dfs(Trie *r) {
  REP(i, 26) {
    if (r->next[i]) {
      Trie *nr = r->next[i];
      dfs(nr);
    }
  }
  REP(i, 26) {
    if (r->ch == i) {
      r->siz[i] = r->cnt;
    } else {
      REP(j, 26) {
        if (r->next[j]) {
          r->siz[i] += r->next[j]->siz[i];
        }
      }
    }
  }
  // if (r->ch == c) {
  //	r->siz[c] = r->cnt;
  //	REP(i, 26) {
  //		if (r->next[i]) {
  //			Trie *nr = r->next[i];
  //			//nr->siz[i] += nr->cnt;
  //			dfs(nr, c);
  //			//r->siz[c] += nr->siz[c];
  //		}
  //	}
  // }
  // else {
  //	REP(i, 26) {
  //		if (r->next[i]) {
  //			Trie *nr = r->next[i];
  //			//nr->siz[i] += nr->cnt;
  //			dfs(nr, c);
  //			r->siz[c] += nr->siz[c];
  //		}
  //	}
  // }
}
void show(Trie *r, string &s) {
  cerr << s << endl;
  REP(i, 26) {
    if (r->next[i]) {
      s += (char)(i + 'a');
      show(r->next[i], s);
      s.pop_back();
    }
  }
}
void solve() {
  // map<pair<string, char>, int>mp;
  int N;
  cin >> N;
  vector<string> v(N);
  REP(i, N) {
    cin >> v[i];
    VREVERSE(v[i]);
  }
  Trie *r = new Trie;
  vector<Trie *> ts;
  REP(i, N) {
    ins(v[i], r);
    while (r->par != (Trie *)0)
      r = r->par;
  }
  // print("a");
  while (r->par != (Trie *)0)
    r = r->par;
  REP(c, 26) {
    dfs(r, c);
    while (r->par != (Trie *)0)
      r = r->par;
  }
  // print("b");
  while (r->par != (Trie *)0)
    r = r->par;
  ll ans = 0;
  string t;
  // show(r, t);
  REP(i, N) {
    // DEBUG(v[i]);
    // show(r, v[i]);
    int n = v[i].size();
    REP(j, n - 1) r = r->next[v[i][j] - 'a'];
    // ans += r->siz[v[i][n - 1] - 'a'] - 1;
    ll res = 0;
    REP(c, 26) {
      if (r->next[c]) {
        res += r->next[c]->siz[v[i][n - 1] - 'a'];
      }
    }
    res--;
    while (r->par != (Trie *)0)
      r = r->par;
    // DEBUG(res);
    ans += res;
  }
  print(ans);
}

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  // int q;
  // cin >> q;
  // while (q--)
  solve();
}