Language: C++

#pragma region Macros
#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define rep2(i, a, b) for(ll i = a; i <= b; ++i)
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define rep3(i, a, b) for(ll i = a; i >= b; --i)
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vll vector<ll>
#define vpi vector<pii>
#define vpll vector<pll>
#define overload2(_1, _2, name, ...) name
#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define VEC(type, name, size)                                                                                                                                  \
    vector<type> name(size);                                                                                                                                   \
    IN(name)
#define vv(type, name, h, ...) vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define VV(type, name, h, w)                                                                                                                                   \
    vector<vector<type>> name(h, vector<type>(w));                                                                                                             \
    IN(name)
#define vvv(type, name, h, w, ...) vector<vector<vector<type>>> name(h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
#define fi first
#define se second
#define all(c) begin(c), end(c)
#define ios ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
using namespace std;
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define Size(c) (int)(c).size()
#define INT(...)                                                                                                                                               \
    int __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define LL(...)                                                                                                                                                \
    ll __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
#define ULL(...)                                                                                                                                               \
    ull __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define STR(...)                                                                                                                                               \
    string __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define CHR(...)                                                                                                                                               \
    char __VA_ARGS__;                                                                                                                                          \
    IN(__VA_ARGS__)
#define DBL(...)                                                                                                                                               \
    double __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define LD(...)                                                                                                                                                \
    ld __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
int scan() { return getchar(); }
template <class T> void scan(T a) { cin >> a; }
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(long double &a) { cin >> a; }
void scan(char a[]) { scanf("%s", a); }
void scan(string &a) { cin >> a; }
template <class T> void scan(vector<T> &);
template <class T, size_t size> void scan(array<T, size> &);
template <class T, class L> void scan(pair<T, L> &);
template <class T, size_t size> void scan(T (&)[size]);
template <class T> void scan(vector<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(deque<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T, size_t size> void scan(array<T, size> &a) {
    for(auto &i : a) scan(i);
}
template <class T, class L> void scan(pair<T, L> &p) {
    scan(p.first);
    scan(p.second);
}
template <class T, size_t size> void scan(T (&a)[size]) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(T &a) { cin >> a; }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &... tail) {
    scan(head);
    IN(tail...);
}
string stin() {
    string s;
    cin >> s;
    return s;
}
template <class T, class S> inline bool chmax(T &a, S b) {

    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T, class S> inline bool chmin(T &a, S b) {

    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}
vi iota(int n) {
    vi a(n);
    iota(all(a), 0);
    return a;
}
template <class T> void UNIQUE(vector<T> &x) {
    sort(all(x));
    x.erase(unique(all(x)), x.end());
}
int in() {
    int x;
    cin >> x;
    return x;
}
ll lin() {
    unsigned long long x;
    cin >> x;
    return x;
}
void print() { putchar(' '); }
void print(bool a) { cout << a; }
void print(int a) { cout << a; }
void print(long long a) { cout << a; }
void print(char a) { cout << a; }
void print(string &a) { cout << a; }
void print(double a) { cout << a; }
template <class T> void print(const vector<T> &);
template <class T, size_t size> void print(const array<T, size> &);
template <class T, class L> void print(const pair<T, L> &p);
template <class T, size_t size> void print(const T (&)[size]);
template <class T> void print(const vector<T> &a) {

    if(a.empty()) return;
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
    cout << endl;
}
template <class T> void print(const deque<T> &a) {

    if(a.empty()) return;
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
}
template <class T, size_t size> void print(const array<T, size> &a) {
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
}
template <class T, class L> void print(const pair<T, L> &p) {
    cout << '(';
    print(p.first);
    cout << ",";
    print(p.second);
    cout << ')';
}
template <class T> void print(set<T> &x) {
    for(auto e : x) print(e), cout << " ";
    cout << endl;
}
template <class T> void print(multiset<T> &x) {
    for(auto e : x) print(e), cout << " ";
    cout << endl;
}
template <class T, size_t size> void print(const T (&a)[size]) {
    print(a[0]);
    for(auto i = a; ++i != end(a);) {
        cout << " ";
        print(*i);
    }
}
template <class T> void print(const T &a) { cout << a; }
int out() {
    putchar('\n');
    return 0;
}
template <class T> int out(const T &t) {
    print(t);
    putchar('\n');
    return 0;
}
template <class Head, class... Tail> int out(const Head &head, const Tail &... tail) {
    print(head);
    putchar(' ');
    out(tail...);
    return 0;
}
ll gcd(ll a, ll b) {
    while(b) {
        ll c = b;
        b = a % b;
        a = c;
    }
    return a;
}
ll lcm(ll a, ll b) {

    if(!a || !b) return 0;
    return a * b / gcd(a, b);
}
vector<pll> factor(ll x) {
    vector<pll> ans;
    for(ll i = 2; i * i <= x; i++)

        if(x % i == 0) {
            ans.push_back({i, 1});
            while((x /= i) % i == 0) ans.back().second++;
        }

    if(x != 1) ans.push_back({x, 1});
    return ans;
}
template <class T> vector<T> divisor(T x) {
    vector<T> ans;
    for(T i = 1; i * i <= x; i++)

        if(x % i == 0) {
            ans.pb(i);

            if(i * i != x) ans.pb(x / i);
        }
    return ans;
}
template <typename T> void zip(vector<T> &x) {
    vector<T> y = x;
    sort(all(y));
    for(int i = 0; i < x.size(); ++i) { x[i] = lb(y, x[i]); }
}
int popcount(ll x) { return __builtin_popcountll(x); }
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int n) { return uniform_int_distribution<int>(0, n - 1)(rng); }
template <typename T> void shuffle(vector<T> &v) {
    rep3(i, v.size() - 1, 1) { swap(v[i], v[rnd(i)]); }
}
#define endl '\n'
vector<string> YES{"NO", "YES"};
vector<string> Yes{"No", "Yes"};
vector<string> yes{"no", "yes"};

#ifdef _LOCAL
#undef endl
#define debug(x)                                                                                                                                               \
    cout << #x << ": ";                                                                                                                                        \
    print(x);                                                                                                                                                  \
    cout << endl;
void err() {}
template <class T> void err(const T &t) {
    print(t);
    cout << " ";
}
template <class Head, class... Tail> void err(const Head &head, const Tail &... tail) {
    print(head);
    putchar(' ');
    out(tail...);
}
#else
#define debug(x)
template <class... T> void err(const T &...) {}
#endif

template <typename T> struct edge {
    int from, to;
    T cost;
    int id;
    edge(int to, T cost) : from(-1), to(to), cost(cost) {}
    edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
    edge(int from, int to, T cost, int id) : from(from), to(to), cost(cost), id(id) {}
    edge &operator=(const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
};
template <typename T> using Edges = vector<edge<T>>;

struct Graph : vector<vector<int>> {
    using vector<vector<int>>::vector;
    Graph(int n, int m) : vector(n) { read(m); }
    inline void add(int a, int b, bool directed = false) {
        (*this)[a].emplace_back(b);

        if(!directed) (*this)[b].emplace_back(a);
    }
    void read(int n = -1, int offset = 1, bool directed = false) {

        if(n == -1) n = this->size() - 1;
        int a, b;
        while(n--) {
            cin >> a >> b;
            Graph::add(a - offset, b - offset, directed);
        }
    }
};
template <typename T> struct WeightedGraph : vector<Edges<T>> {
    using vector<Edges<T>>::vector;
    inline void add(int a, int b, T c, bool directed = false) {
        (*this)[a].emplace_back(b, c);

        if(!directed) (*this)[b].emplace_back(a, c);
    }
    void read(int n = -1, int offset = 1) {

        if(n == -1) n = this->size() - 1;
        int a, b;
        T c;
        while(n--) {
            cin >> a >> b >> c;
            WeightedGraph::add(a - offset, b - offset, c);
        }
    }
};
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(15);
    }
} setup_io;
#pragma endregion

// _________コーディングはここから！！___________
constexpr int N = 1000001;
struct RollingHash {
    unsigned h1[N], h2[N], p1[N], p2[N];
    const unsigned mod1 = 1000000007, mod2 = 998244353;
    unsigned b1, b2;
    inline unsigned mul1(unsigned a, unsigned b) const {
        unsigned long long x = (unsigned long long)a * b;
        unsigned xh = (unsigned)(x >> 32), xl = (unsigned)x, d, m;
        asm("divl %4; \n\t" : "=a"(d), "=d"(m) : "d"(xh), "a"(xl), "r"(mod1));
        return m;
    }
    inline unsigned mul2(unsigned a, unsigned b) const {
        unsigned long long x = (unsigned long long)a * b;
        unsigned xh = (unsigned)(x >> 32), xl = (unsigned)x, d, m;
        asm("divl %4; \n\t" : "=a"(d), "=d"(m) : "d"(xh), "a"(xl), "r"(mod2));
        return m;
    }

    RollingHash(const string &s) : b1(rnd(100000)), b2(rnd(100000)) {
        int sz = (int)s.size();
        h1[0] = h2[0] = 0;
        p1[0] = p2[0] = 1;
        for(int i = 0; i < sz; i++) {
            h1[i + 1] = mul1(h1[i], b1) + s[i], p1[i + 1] = mul1(p1[i], b1);
            h2[i + 1] = mul2(h2[i], b2) + s[i], p2[i + 1] = mul2(p2[i], b2);
            if(h1[i + 1] >= mod1) h1[i + 1] -= mod1;
            if(h2[i + 1] >= mod2) h2[i + 1] -= mod2;
        }
    }

    unsigned long long int get(int l, int r) const {
        unsigned r1 = h1[r] + mod1 - mul1(h1[l], p1[r - l]);
        unsigned r2 = h2[r] + mod2 - mul2(h2[l], p2[r - l]);
        if(r1 >= mod1) r1 -= mod1;
        if(r2 >= mod2) r2 -= mod2;
        return (unsigned long long int)r2 * mod1 + r1;
    }

    unsigned long long int connect(unsigned long long int h1, unsigned long long int h2, int h2len) const {
        unsigned long long int r1 = mul1(h1 % mod1, p1[h2len]) + h2 % mod1;
        unsigned long long int r2 = mul2(h1 / mod1, p2[h2len]) + h2 / mod2;
        if(r1 >= mod1) r1 -= mod1;
        if(r2 >= mod2) r2 -= mod2;
        return (unsigned long long int)r2 * mod1 + r1;
    }

    int LCP(const RollingHash &b, int l1, int r1, int l2, int r2) {
        int len = min(r1 - l1, r2 - l2);
        int low = -1, high = len + 1;
        while(high - low > 1) {
            int mid = (low + high) / 2;
            if(get(l1, l1 + mid) == b.get(l2, l2 + mid))
                low = mid;
            else
                high = mid;
        }
        return (low);
    }
    RollingHash() = default;
};

using u8 = unsigned char;
using u32 = unsigned int;
using u64 = unsigned long long int;
template <typename KeyT, typename ValT, typename Hash, ValT Z = ValT()> class hash_map {
    int n;
    u32 sz;
    std::vector<u64> s;
    std::vector<std::pair<KeyT, ValT>> v;
    Hash hash;
    static constexpr ValT nf = Z;

    bool test(u32 i, const std::vector<u64> &t) const { return !!(t[i / 64] & (1ULL << (i % 64))); }
    void set(u32 i, std::vector<u64> &t) { t[i / 64] |= 1ULL << (i % 64); }

    u32 find(const KeyT &a) const {
        u32 ind = hash(a, n);
        u32 i;
        for(i = ind; i < ind + (1 << n); ++i) {
            u32 j = i & ((1 << n) - 1);
            if(!test(j, s)) return j;
            if(v[j].first == a) return j;
        }
        return -1;
    }

    void reallocate() {
        ++n;
        std::vector<u64> t(1 << (n - 6));
        std::vector<std::pair<KeyT, ValT>> w(1 << n);
        for(u32 i = 0; i < v.size(); ++i) {
            if(!test(i, s)) continue;
            u32 j = hash(v[i].first, n);
            while(test(j, t)) ++j, j &= (1 << n) - 1;
            set(j, t);
            w[j] = v[i];
        }

        s.swap(t);
        v.swap(w);
    }

  public:
    hash_map() : n(10), sz(0), s(1 << (n - 6)), v(1 << n) {}

    ValT &operator[](const KeyT &a) {
        u32 i = find(a);
        if(v[i].first == a) return v[i].second;

        ++sz;
        if(sz + sz / 2 >= (1U << n)) {
            reallocate();
            i = find(a);
        }
        set(i, s);
        v[i].first = a;
        return v[i].second = Z;
    }

    const ValT &at(const KeyT &a) const {
        u32 i = find(a);
        return test(i, s) ? v[i].second : nf;
    }

    u32 size() const { return sz; }
};

struct hash_u64 {
    u32 operator()(u64 a, int n) const {
        static constexpr u64 r = 11995408973635179863ULL;
        return a * r >> (64 - n);
    }
};
template <const int sz = 5 * 10000000, typename T = long long> struct IO {
    char reader[sz], writer[sz];
    char *now, *now2 = writer;
    IO() {
        reader[fread(reader, sizeof(char), sizeof(char) * sz, stdin)];
        now = reader;
    }
    inline T read() {
        while(*now && *now <= 32) now++;
        if(*now == '-') {
            now++;
            T res = 0;
            while('0' <= *now and *now <= '9') { res = res * 10 + *now++ - '0'; }
            return -res;
        } else {
            T res = 0;
            while('0' <= *now and *now <= '9') { res = res * 10 + *now++ - '0'; }
            return res;
        }
    }
    inline string read_str() {
        string res;
        while(!*now or *now == '\n' or *now == ' ') now++;
        while(*now and *now != '\n' and *now != ' ') res += *now++;
        now++;
        return res;
    }
    inline void write(T x, char margin = ' ') {
        if(x == 0) {
            putchar('0');
            putchar(margin);
            return;
        }
        if(x < 0) {
            putchar('-');
            x = -x;
        }
        while(x) {
            *now2 = '0' + x % 10;
            now2++;
            x /= 10;
        }
        do {
            now2--;
            putchar(*now2);
        } while(now2 != writer);
        putchar(margin);
    }
    inline void write_str(string s, char margin = ' ') {
        for(auto c : s) putchar(c);
        putchar(margin);
    }
};
IO io;
inline ll read() { return io.read(); }
inline void write(ll x) { io.write(x); }
inline void write(ll x, char c) { io.write(x, c); }
main() {
    int n = read();
    vector<string> v(n);
    rep(i, n) v[i] = io.read_str(), reverse(all(v[i]));
    vi cnt(1000001);
    sort(all(v), [&](string &s, string &t) { return s.size() < t.size(); });
    vi st(n);
    string s;
    rep(i, n) {
        st[i] = s.size();
        s += v[i];
    }
    RollingHash rh(s);
    hash_map<u64, u64, hash_u64> mp;
    ll ans = 0;
    vector<u64> mem(26);
    rep(i, 26) { mem[i] = (u64)(rh.mod1 + 1) * (u64)('a' + i); }
    rep(i, n) {
        int mask = 0;
        rep3(j, v[i].size() - 1, 0) {
            mask |= (1 << (v[i][j] - 'a'));
            ll now = rh.get(st[i], st[i] + j);
            if(cnt[j + 1]) ans += popcount(mp[rh.connect(now, rh.get(used[k], used[k] + 1), 1)] & mask);
        }
        mp[rh.get(st[i], st[i] + v[i].size())]++;
        cnt[v[i].size()]++;
    }
    cout << ans << endl;
}


Compiler output:
a.cc:531:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  531 | main() {
      | ^~~~
a.cc: In function 'int main()':
a.cc:553:70: error: 'used' was not declared in this scope
  553 |             if(cnt[j + 1]) ans += popcount(mp[rh.connect(now, rh.get(used[k], used[k] + 1), 1)] & mask);
      |                                                                      ^~~~
a.cc:553:75: error: 'k' was not declared in this scope
  553 |             if(cnt[j + 1]) ans += popcount(mp[rh.connect(now, rh.get(used[k], used[k] + 1), 1)] & mask);
      |                                                                           ^