結果

問題 No.599 回文かい
コンテスト
ユーザー tokusakurai
提出日時 2020-07-08 18:16:46
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 112 ms / 4,000 ms
コード長 4,372 bytes
コンパイル時間 1,827 ms
コンパイル使用メモリ 171,728 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-10-04 08:41:41
合計ジャッジ時間 3,156 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
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ファイルパターン 結果
other AC * 22
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define elif else if
#define sp(x) fixed << setprecision(x)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
const ld EPS = 1e-10;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

template<ll mod>
struct Mod_Int{
    ll x;
    Mod_Int() {}
    Mod_Int(ll y) : x (y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    Mod_Int &operator += (const Mod_Int &p){
        x = (x + p.x) % mod;
        return *this;
    }

    Mod_Int &operator -= (const Mod_Int &p){
        x = (x + mod - p.x) % mod;
        return *this;
    }

    Mod_Int &operator *= (const Mod_Int &p){
        x = (x * p.x) % mod;
        return *this;
    }

    Mod_Int &operator /= (const Mod_Int &p){
        *this *= p.inverse();
        return *this;
    }

    Mod_Int &operator ++ () {return *this += Mod_Int(1);}

    Mod_Int operator ++ (int){
        Mod_Int tmp = *this;
        ++*this;
        return tmp;
    }

    Mod_Int &operator -- () {return *this -= Mod_Int(1);}

    Mod_Int operator -- (int){
        Mod_Int tmp = *this;
        --*this;
        return tmp;
    }

    Mod_Int operator - () const {return Mod_Int(-x);}

    Mod_Int operator + (const Mod_Int &p) const {return Mod_Int(*this) += p;}

    Mod_Int operator - (const Mod_Int &p) const {return Mod_Int(*this) -= p;}

    Mod_Int operator * (const Mod_Int &p) const {return Mod_Int(*this) *= p;}

    Mod_Int operator / (const Mod_Int &p) const {return Mod_Int(*this) /= p;}

    bool operator == (const Mod_Int &p) const {return x == p.x;}

    bool operator != (const Mod_Int &p) const {return x != p.x;}

    Mod_Int pow (ll n) const{
        Mod_Int now = *this, ret = 1;
        while(n > 0){
            if(n & 1) ret *= now;
            now *= now, n >>= 1;
        }
        return ret;
    }

    Mod_Int inverse () const{
        return pow(mod-2);
    }

    friend ostream &operator << (ostream &os, const Mod_Int &p){
        return os << p.x;
    }

    friend istream &operator >> (istream &is, Mod_Int &p){
        ll a;
        is >> a;
        p = Mod_Int<mod>(a);
        return is;
    }
};

using mint = Mod_Int<MOD>;
const int MAX_N = 1e6;
mint fac[MAX_N+1], ifac[MAX_N+1];

void init(){
    fac[0] = 1;
    rep2(i, 1, MAX_N){
        fac[i] = fac[i-1]*i;
    }
    ifac[MAX_N] = fac[MAX_N].inverse();
    rep3(i, MAX_N, 1){
        ifac[i-1] = ifac[i]*i;
    }
}

mint comb(int n, int k){
    return fac[n]*ifac[n-k]*ifac[k];
}

mint perm(int n, int k){
    return fac[n]*ifac[n-k];
}

using ull = unsigned long long;

template<ull base>
struct Rolling_Hash{
    ull mod = (1UL<<61)-1;
    vector<ull> hashed, pw;

    ull mul(ull a, ull b) const{
        ull a1 = a>>31, a2 = a&((1UL<<31)-1);
        ull b1 = b>>31, b2 = b&((1UL<<31)-1);
        ull ret = 2*a1*b1+a2*b2, c = a1*b2+a2*b1;
        ull c1 = c>>30, c2 = c&((1UL<<30)-1);
        ret += c1 + (c2<<31);
        ret = (ret>>61) + ret&mod;
        if(ret >= mod) ret -= mod;
        return ret;
    }

    Rolling_Hash(const string &s){
        int n = sz(s);
        hashed.assign(n+1, 0);
        pw.assign(n+1, 0);
        pw[0] = 1;
        rep(i, n){
            pw[i+1] = mul(pw[i], base);
            hashed[i+1] = mul(hashed[i], base)+s[i];
            if(hashed[i+1] >= mod) hashed[i+1] -= mod;
        }
    }

    ull get(int l, int r) const{
        ull ret = hashed[r]+mod-mul(hashed[l], pw[r-l]);
        if(ret >= mod) ret -= mod;
        return ret;
    }
};

using RH = Rolling_Hash<MOD>;

int main(){
    string S;
    cin >> S;
    int N = sz(S);
    mint dp[N/2+1];
    fill(dp, dp+(N/2+1), 1);
    RH rh(S);
    rep3(i, N/2, 0){
        rep2(j, 1, N/2-i){
            if(rh.get(i, i+j) == rh.get(N-i-j, N-i)) dp[i] += dp[i+j];
        }
    }
    cout << dp[0] << endl;
}
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