#ifdef LOCAL //#define _GLIBCXX_DEBUG #else #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") //#pragma GCC target("avx512f,avx512dq,avx512cd,avx512bw,avx512vl") #endif #include using namespace std; #include #include #include #include #include namespace atcoder { namespace internal { std::vector sa_naive(const std::vector& s) { int n = int(s.size()); std::vector sa(n); std::iota(sa.begin(), sa.end(), 0); std::sort(sa.begin(), sa.end(), [&](int l, int r) { if (l == r) return false; while (l < n && r < n) { if (s[l] != s[r]) return s[l] < s[r]; l++; r++; } return l == n; }); return sa; } std::vector sa_doubling(const std::vector& s) { int n = int(s.size()); std::vector sa(n), rnk = s, tmp(n); std::iota(sa.begin(), sa.end(), 0); for (int k = 1; k < n; k *= 2) { auto cmp = [&](int x, int y) { if (rnk[x] != rnk[y]) return rnk[x] < rnk[y]; int rx = x + k < n ? rnk[x + k] : -1; int ry = y + k < n ? rnk[y + k] : -1; return rx < ry; }; std::sort(sa.begin(), sa.end(), cmp); tmp[sa[0]] = 0; for (int i = 1; i < n; i++) { tmp[sa[i]] = tmp[sa[i - 1]] + (cmp(sa[i - 1], sa[i]) ? 1 : 0); } std::swap(tmp, rnk); } return sa; } // SA-IS, linear-time suffix array construction // Reference: // G. Nong, S. Zhang, and W. H. Chan, // Two Efficient Algorithms for Linear Time Suffix Array Construction template std::vector sa_is(const std::vector& s, int upper) { int n = int(s.size()); if (n == 0) return {}; if (n == 1) return {0}; if (n == 2) { if (s[0] < s[1]) { return {0, 1}; } else { return {1, 0}; } } if (n < THRESHOLD_NAIVE) { return sa_naive(s); } if (n < THRESHOLD_DOUBLING) { return sa_doubling(s); } std::vector sa(n); std::vector ls(n); for (int i = n - 2; i >= 0; i--) { ls[i] = (s[i] == s[i + 1]) ? ls[i + 1] : (s[i] < s[i + 1]); } std::vector sum_l(upper + 1), sum_s(upper + 1); for (int i = 0; i < n; i++) { if (!ls[i]) { sum_s[s[i]]++; } else { sum_l[s[i] + 1]++; } } for (int i = 0; i <= upper; i++) { sum_s[i] += sum_l[i]; if (i < upper) sum_l[i + 1] += sum_s[i]; } auto induce = [&](const std::vector& lms) { std::fill(sa.begin(), sa.end(), -1); std::vector buf(upper + 1); std::copy(sum_s.begin(), sum_s.end(), buf.begin()); for (auto d : lms) { if (d == n) continue; sa[buf[s[d]]++] = d; } std::copy(sum_l.begin(), sum_l.end(), buf.begin()); sa[buf[s[n - 1]]++] = n - 1; for (int i = 0; i < n; i++) { int v = sa[i]; if (v >= 1 && !ls[v - 1]) { sa[buf[s[v - 1]]++] = v - 1; } } std::copy(sum_l.begin(), sum_l.end(), buf.begin()); for (int i = n - 1; i >= 0; i--) { int v = sa[i]; if (v >= 1 && ls[v - 1]) { sa[--buf[s[v - 1] + 1]] = v - 1; } } }; std::vector lms_map(n + 1, -1); int m = 0; for (int i = 1; i < n; i++) { if (!ls[i - 1] && ls[i]) { lms_map[i] = m++; } } std::vector lms; lms.reserve(m); for (int i = 1; i < n; i++) { if (!ls[i - 1] && ls[i]) { lms.push_back(i); } } induce(lms); if (m) { std::vector sorted_lms; sorted_lms.reserve(m); for (int v : sa) { if (lms_map[v] != -1) sorted_lms.push_back(v); } std::vector rec_s(m); int rec_upper = 0; rec_s[lms_map[sorted_lms[0]]] = 0; for (int i = 1; i < m; i++) { int l = sorted_lms[i - 1], r = sorted_lms[i]; int end_l = (lms_map[l] + 1 < m) ? lms[lms_map[l] + 1] : n; int end_r = (lms_map[r] + 1 < m) ? lms[lms_map[r] + 1] : n; bool same = true; if (end_l - l != end_r - r) { same = false; } else { while (l < end_l) { if (s[l] != s[r]) { break; } l++; r++; } if (l == n || s[l] != s[r]) same = false; } if (!same) rec_upper++; rec_s[lms_map[sorted_lms[i]]] = rec_upper; } auto rec_sa = sa_is(rec_s, rec_upper); for (int i = 0; i < m; i++) { sorted_lms[i] = lms[rec_sa[i]]; } induce(sorted_lms); } return sa; } } // namespace internal std::vector suffix_array(const std::vector& s, int upper) { assert(0 <= upper); for (int d : s) { assert(0 <= d && d <= upper); } auto sa = internal::sa_is(s, upper); return sa; } template std::vector suffix_array(const std::vector& s) { int n = int(s.size()); std::vector idx(n); iota(idx.begin(), idx.end(), 0); sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; }); std::vector s2(n); int now = 0; for (int i = 0; i < n; i++) { if (i && s[idx[i - 1]] != s[idx[i]]) now++; s2[idx[i]] = now; } return internal::sa_is(s2, now); } std::vector suffix_array(const std::string& s) { int n = int(s.size()); std::vector s2(n); for (int i = 0; i < n; i++) { s2[i] = s[i]; } return internal::sa_is(s2, 255); } // Reference: // T. Kasai, G. Lee, H. Arimura, S. Arikawa, and K. Park, // Linear-Time Longest-Common-Prefix Computation in Suffix Arrays and Its // Applications template std::vector lcp_array(const std::vector& s, const std::vector& sa) { int n = int(s.size()); assert(n >= 1); std::vector rnk(n); for (int i = 0; i < n; i++) { rnk[sa[i]] = i; } std::vector lcp(n - 1); int h = 0; for (int i = 0; i < n; i++) { if (h > 0) h--; if (rnk[i] == 0) continue; int j = sa[rnk[i] - 1]; for (; j + h < n && i + h < n; h++) { if (s[j + h] != s[i + h]) break; } lcp[rnk[i] - 1] = h; } return lcp; } std::vector lcp_array(const std::string& s, const std::vector& sa) { int n = int(s.size()); std::vector s2(n); for (int i = 0; i < n; i++) { s2[i] = s[i]; } return lcp_array(s2, sa); } // Reference: // D. Gusfield, // Algorithms on Strings, Trees, and Sequences: Computer Science and // Computational Biology template std::vector z_algorithm(const std::vector& s) { int n = int(s.size()); if (n == 0) return {}; std::vector z(n); z[0] = 0; for (int i = 1, j = 0; i < n; i++) { int& k = z[i]; k = (j + z[j] <= i) ? 0 : std::min(j + z[j] - i, z[i - j]); while (i + k < n && s[k] == s[i + k]) k++; if (j + z[j] < i + z[i]) j = i; } z[0] = n; return z; } std::vector z_algorithm(const std::string& s) { int n = int(s.size()); std::vector s2(n); for (int i = 0; i < n; i++) { s2[i] = s[i]; } return z_algorithm(s2); } } // namespace atcoder using namespace atcoder; // AC-Library -> https://atcoder.github.io/ac-library/production/document_ja/ typedef long long ll; typedef unsigned long long ull; typedef long double ld; typedef pair P; typedef pair Pi; typedef vector Vec; typedef vector Vi; typedef vector Vs; typedef vector Vc; typedef vector

VP; typedef vector VVP; typedef vector VV; typedef vector VVi; typedef vector VVc; typedef vector VVV; typedef vector VVVV; #define MAKEVV(variable, a, ...) VV variable(a, Vec(__VA_ARGS__)) #define MAKEVVc(variable, a, ...) VVc variable(a,Vc(__VA_ARGS__)) #define MAKEVVV(variable, a, b, ...) VVV variable(a, VV(b, Vec(__VA_ARGS__))) #define MAKEVVVV(variable, a, b, c, ...) VVVV variable(a, VVV(b, (VV(c, Vec(__VA_ARGS__))))) #define endl '\n' #define REP(i, a, b) for(ll i=(a); i<(b); i++) #define PER(i, a, b) for(ll i=(a); i>=(b); i--) #define rep(i, n) REP(i, 0, n) #define per(i, n) PER(i, n, 0) const ll INF = 4'000'000'000'000'000'010LL; const ll MOD=998244353; #define Yes(n) cout << ((n) ? "Yes" : "No") << endl; #define YES(n) cout << ((n) ? "YES" : "NO") << endl; #define ALL(v) v.begin(), v.end() #define rALL(v) v.rbegin(), v.rend() #define pb(x) push_back(x) #define mp(a, b) make_pair(a,b) #define Each(a,b) for(auto &a :b) #define rEach(i, mp) for (auto i = mp.rbegin(); i != mp.rend(); ++i) #define SUM(a) accumulate(ALL(a),0LL) #define outminusone(a) cout<< ( a==INF ? -1 : a ) <bool chmax(T &a, const S &b) { if (abool chmin(T &a, const S &b) { if (bauto lb(vector &X, T x){return lower_bound(ALL(X),x) - X.begin();} templateauto ub(vector &X, T x){return upper_bound(ALL(X),x) - X.begin();} ll popcnt(ll x){return __builtin_popcount(x);} ll topbit(ll t){return t==0?-1:63-__builtin_clzll(t);} ll floor(ll y,ll x){assert(x != 0);if(x < 0){y *= -1; x *= -1;}if(y < 0){return (y-x+1)/x;}return y/x;}; ll ceil(ll y, ll x){assert(x != 0);if(x < 0){y *= -1; x *= -1;}if(y < 0){return y/x;}return (y+x-1)/x;}; templateistream &operator>>(istream &i, pair &p) { return i>>p.first>>p.second; } templateistream& operator>>(istream&i,vector&v){rep(j,v.size())i>>v[j];return i;} templateostream &operator<<(ostream &s, const pair &p) { return s<<"("<ostream &operator<<(ostream &os, const vector &v) {bool f = false;for(const auto &d: v) {if(f) os<<" ";f = true;os< ostream& operator<<(ostream& os, const set& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";} template ostream& operator<<(ostream& os, const multiset& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";} templateostream &operator<<(ostream &os, const map &s) {bool f = false;os< void out(const Head &head, const Tail &...tail) {cout << head;if(sizeof...(tail)) cout << ' ';out(tail...);} #ifdef LOCAL templateostream &operator<<(ostream &s, const vector> &vv) {int len=vv.size();for(int i=0; i auto operator<<(T&& x) {if (!first) os << ", ";first = false;os << x;return *this;}}; template void dbg0(T&&... t) {(PrettyOS{cerr, true} << ... << t);} #define dbg(...)do {cerr << #__VA_ARGS__ << ": ";dbg0(__VA_ARGS__);cerr << endl;} while (false); #else #define dbg(...) #endif template ll binary_search(F check, ll ok, ll ng, bool check_ok = true) { if (check_ok) assert(check(ok)); while (abs(ok - ng) > 1) { auto x = (ng + ok) / 2; tie(ok, ng) = (check(x) ? mp(x, ng) : mp(ok, x)); } return ok; } int solve(){ ll n; string s; cin>>n>>s; auto z = z_algorithm(s); dbg(z); ll ans = 0; REP(i,1,n){ if(i < z[i]) ans++; else if (i == z[i]){ if(i < n - i)ans++; }else{ ll k = z[i]; if(i + k < n and s[k] < s[i+k])ans++; } } out(ans); return 0; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); cout<>T; while(T--) solve(); }