結果

問題 No.2454 Former < Latter
ユーザー hamathhamath
提出日時 2023-09-01 22:51:36
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
WA  
実行時間 -
コード長 13,047 bytes
コンパイル時間 3,875 ms
コンパイル使用メモリ 244,904 KB
最終ジャッジ日時 2025-02-16 17:08:22
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 14 WA * 9
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ソースコード

diff # 

#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 <bits/stdc++.h>
using namespace std;


#include <algorithm>
#include <cassert>
#include <numeric>
#include <string>
#include <vector>

namespace atcoder {

namespace internal {

std::vector<int> sa_naive(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> 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<int> sa_doubling(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> 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 <int THRESHOLD_NAIVE = 10, int THRESHOLD_DOUBLING = 40>
std::vector<int> sa_is(const std::vector<int>& 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<int> sa(n);
    std::vector<bool> 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<int> 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<int>& lms) {
        std::fill(sa.begin(), sa.end(), -1);
        std::vector<int> 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<int> 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<int> 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<int> sorted_lms;
        sorted_lms.reserve(m);
        for (int v : sa) {
            if (lms_map[v] != -1) sorted_lms.push_back(v);
        }
        std::vector<int> 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<THRESHOLD_NAIVE, THRESHOLD_DOUBLING>(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<int> suffix_array(const std::vector<int>& 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 <class T> std::vector<int> suffix_array(const std::vector<T>& s) {
    int n = int(s.size());
    std::vector<int> idx(n);
    iota(idx.begin(), idx.end(), 0);
    sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; });
    std::vector<int> 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<int> suffix_array(const std::string& s) {
    int n = int(s.size());
    std::vector<int> 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 <class T>
std::vector<int> lcp_array(const std::vector<T>& s,
                           const std::vector<int>& sa) {
    int n = int(s.size());
    assert(n >= 1);
    std::vector<int> rnk(n);
    for (int i = 0; i < n; i++) {
        rnk[sa[i]] = i;
    }
    std::vector<int> 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<int> lcp_array(const std::string& s, const std::vector<int>& sa) {
    int n = int(s.size());
    std::vector<int> 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 <class T> std::vector<int> z_algorithm(const std::vector<T>& s) {
    int n = int(s.size());
    if (n == 0) return {};
    std::vector<int> 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<int> z_algorithm(const std::string& s) {
    int n = int(s.size());
    std::vector<int> 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<ll, ll> P;
typedef pair<int, int> Pi;
typedef vector<ll> Vec;
typedef vector<int> Vi;
typedef vector<string> Vs;
typedef vector<char> Vc;
typedef vector<P> VP;
typedef vector<VP> VVP;
typedef vector<Vec> VV;
typedef vector<Vi> VVi;
typedef vector<Vc> VVc;
typedef vector<VV> VVV;
typedef vector<VVV> 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 ) <<endl
#define Uniq(v) v.erase(unique(v.begin(), v.end()), v.end())
#define fi first
#define se second

template<class T, class S>bool chmax(T &a, const S &b) { if (a<b) { a=b; return true; } return false; }
template<class T, class S>bool chmin(T &a, const S &b) { if (b<a) { a=b; return true; } return false; }
template<class T>auto lb(vector<T> &X, T x){return lower_bound(ALL(X),x) - X.begin();}
template<class T>auto ub(vector<T> &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;};

template<typename T1, typename T2>istream &operator>>(istream &i, pair<T1, T2> &p) { return i>>p.first>>p.second; }
template<typename T>istream& operator>>(istream&i,vector<T>&v){rep(j,v.size())i>>v[j];return i;}
template<typename T1, typename T2>ostream &operator<<(ostream &s, const pair<T1, T2> &p) { return s<<"("<<p.first<<", "<<p.second<<")"; }
template<class T>ostream &operator<<(ostream &os, const vector<T> &v) {bool f = false;for(const auto &d: v) {if(f) os<<" ";f = true;os<<d;}return os;}
template <class T> ostream& operator<<(ostream& os, const set<T>& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";}
template <class T> ostream& operator<<(ostream& os, const multiset<T>& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";}
template<class T, class U>ostream &operator<<(ostream &os, const map<T, U> &s) {bool f = false;os<<endl;for(auto p: s) {if(f) os<<endl;f = true;os<<p.first<<": "<<p.second;}return os<<endl;}
void out() { cout << endl; }
template <class Head, class... Tail> void out(const Head &head, const Tail &...tail) {cout << head;if(sizeof...(tail)) cout << ' ';out(tail...);}

#ifdef LOCAL
template<typename T>ostream &operator<<(ostream &s, const vector<vector<T>> &vv) {int len=vv.size();for(int i=0; i<len; ++i) {if(i==0)s<<endl;s<<i<<":"<<vv[i];if(i!=len-1)s<<endl;}return s;}
struct PrettyOS {ostream& os;bool first;template <class T> auto operator<<(T&& x) {if (!first) os << ", ";first = false;os << x;return *this;}};
template <class... T> 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 <typename F>
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 sa = suffix_array(s);
    //dbg(sa);
//    string t;
//    t += s[0];
//    string tr = {s[0], s[1]};
//    tr[1] += 1;
    //dbg(t,tr);
    //   t <= former < tr
    // tr <= lat_iなら form < latが確定
    // lat_i < tならlat > formが確定
    Vec v;
    rep(i,n){
        if(sa[i] != 0){
            v.pb(sa[i]);
        }
    }
    n--;

    dbg(v);
    auto nibutan = [&](ll ok, ll ng, auto f)->ll {
        while (abs(ok-ng) > 1) {
            ll mid = (ok+ng)/2;
            tie(ok, ng) = (f(mid) ? mp(mid, ng) : mp(ok, mid));
        }
        return ok;
    };
    auto judge = [&](ll mid)->bool{
        dbg(mid,s.substr(0,v[mid]),s.substr(v[mid]))
        return s.substr(0,v[mid]) < s.substr(v[mid]);
    };
    ll L = nibutan(n,-1,judge);
    out(n - L);
    return  0;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout<<std::setprecision(20);
    ll T;
    cin>>T;
    while(T--)
    solve();
}
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