#include #define rep(i,a,b) for(int i=a;i=b;i--) #define fore(i,a) for(auto &i:a) #pragma GCC optimize ("-O3") using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); } //--------------------------------------------------------------------------------------------------- template struct ModInt { static const int Mod = MOD; unsigned x; ModInt() : x(0) { } ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; } ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; } int get() const { return (int)x; } ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; } ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; } ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; } ModInt &operator/=(ModInt that) { return *this *= that.inverse(); } ModInt operator+(ModInt that) const { return ModInt(*this) += that; } ModInt operator-(ModInt that) const { return ModInt(*this) -= that; } ModInt operator*(ModInt that) const { return ModInt(*this) *= that; } ModInt operator/(ModInt that) const { return ModInt(*this) /= that; } ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } return ModInt(u); } bool operator==(ModInt that) const { return x == that.x; } bool operator!=(ModInt that) const { return x != that.x; } ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; } }; template ostream& operator<<(ostream& st, const ModInt a) { st << a.get(); return st; }; template ModInt operator^(ModInt a, unsigned long long k) { ModInt r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; } typedef ModInt<1000000007> mint; #ifdef _MSC_VER inline unsigned int __builtin_clz(unsigned int x){unsigned long r;_BitScanReverse(&r,x);return 31-r;} inline int __lg(int __n) { return sizeof(int) * 8 - 1 - __builtin_clz(__n); } #endif template struct IRMQ { int n; T *d; IRMQ() : n(0), d(NULL) {} template IRMQ(Iter begin, Iter end) : n(0), d(0) { build(begin, end); } IRMQ(const IRMQ &y) : n(y.n), d(NULL) { if (y.n) build(y.d[0], y.d[0] + n); } IRMQ(IRMQ &&y) : n(0), d(NULL) { swap(*this, y); } ~IRMQ() { if (n) { n = 0; delete d; d = NULL; } } friend void swap(IRMQ &x, IRMQ &y) { swap(x.n, y.n); swap(x.d, y.d); } IRMQ& operator=(IRMQ y) { swap(*this, y); return *this; } template void build(Iter begin, Iter end) { // random access iterator n = end - begin; if (n == 0) return; int g = __lg(n); d = new T[n*(g + 1)]; rep(i, 0, n) { d[i] = *begin; ++begin; } for (int t = 0, b = 0; t sa, lcp, rank; SAIS() {} SAIS(const string &str_) { N = str.size() + 1; S = vector(N, 0); for (int i = 0; i &S_, int A_SIZE_, bool lcp_flag = true) : S(S_), A_SIZE(A_SIZE_) { buildSA(); if (lcp_flag) buildLCP(); } void init(const string &str_) { str = str_; N = str.size() + 1; S = vector(N, 0); for (int i = 0; i S; int A_SIZE; int N; vector t, B; enum { STYPE, LTYPE }; inline bool is_lms(int i) { return i>0 && t[i] == STYPE && t[i - 1] == LTYPE; } void bucket() { B = vector(A_SIZE); for (int i = 0; i= 0 && S[j] >= S[j + 1]) sa[B[S[j] - 1]++] = j; } bucket(); for (int i = N; i--; ) { int j = sa[i] - 1; if (j >= 0 && S[j] <= S[j + 1]) sa[--B[S[j]]] = j; } } void buildSA() { N = S.size(); sa.assign(N, -1); if (N == 1) { sa[0] = 0; return; } t.assign(N, STYPE); for (int i = N - 1; i--;) if (S[i] > S[i + 1] || (S[i] == S[i + 1] && t[i + 1] == LTYPE)) t[i] = LTYPE; bucket(); for (int i = N; i--;) if (is_lms(i)) sa[--B[S[i]]] = i; induced_sort(); int N1 = 0; for (int i = 0; i0 && is_lms(cur + j)) break; if (S[cur + j] != S[prev + j]) diff = true; } if (diff) name++; sa[N1 + cur / 2] = name - 1; prev = cur; } vector S1, sa1(N1); for (int i = N1; i= 0) S1.push_back(sa[i]); if (name == N1) for (int i = 0; i0) h--; for (; j + h rmq; void buildRMQ() { rmq = IRMQ(lcp.begin(), lcp.end()); } int common_prefix(int x, int y) { if (x == y) return N - 1 - x; if (y >= N - 1) return 0; if (rank[x] > rank[y]) swap(x, y); return rmq.min_v(rank[x], rank[y]); } int compare(int x, int xn, int y, int yn) { int l = common_prefix(x, y); if (l >= xn || l >= yn) return xn < yn ? -1 : xn == yn ? 0 : 1; return rank[x] < rank[y] ? -1 : x == y ? 0 : 1; } }; /*---------------------------------------------------------------------------------------------------             ∧_∧       ∧_∧  (´<_` )  Welcome to My Coding Space!      ( ´_ゝ`) /  ⌒i     /   \    | |     /   / ̄ ̄ ̄ ̄/  |   __(__ニつ/  _/ .| .|____      \/____/ (u ⊃ ---------------------------------------------------------------------------------------------------*/ string S; int N; SAIS sais; //--------------------------------------------------------------------------------------------------- mint memo[10101]; int vis[10101]; mint f(int L, int R) { if (vis[L]) return memo[L]; mint res = 1; int l = L + 1, r = R - 1, n = 1; while (l <= r) { if (n <= sais.common_prefix(L, r + 1)) res += f(l, r); l++; r--; n++; } vis[L] = 1; return memo[L] = res; } //--------------------------------------------------------------------------------------------------- void _main() { cin >> S; N = S.length(); sais.init(S); sais.buildRMQ(); cout << f(0, N - 1) << endl; }