結果

問題 No.599 回文かい
ユーザー paruki
提出日時 2017-11-29 14:58:23
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 99 ms / 4,000 ms
コード長 3,468 bytes
コンパイル時間 1,502 ms
コンパイル使用メモリ 173,124 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-11-27 18:55:48
合計ジャッジ時間 2,826 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
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ファイルパターン 結果
other AC * 22
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ソースコード

diff #
プレゼンテーションモードにする

#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
struct RollingHash {
    static const int C = 31, C2 = 29, P = 1000000007, P2 = 1000000009;
    int _n;
    vector<long long> pw, pw2, hs, hs2;
    RollingHash() {}
    RollingHash(const string &st)
        :_n((int)st.size()), pw(_n + 1), pw2(_n + 1), hs(_n + 1), hs2(_n + 1)
    {
        pw[0] = pw2[0] = 1;
        rep(i, _n) {
            pw[i + 1] = (pw[i] * C) % P;
            pw2[i + 1] = (pw2[i] * C2) % P2;
            hs[i + 1] = (C*hs[i] + st[i]) % P;
            hs2[i + 1] = (C2*hs2[i] + st[i]) % P2;
        }
    }
    // [l, r)
    pii getHash(int l, int r) {
        int res, res2;
        res = (hs[r] - hs[l] * pw[r - l]) % P;
        res2 = (hs2[r] - hs2[l] * pw2[r - l]) % P2;
        if (res < 0)res += P;
        if (res2 < 0)res2 += P2;
        return mp(res, res2);
    }
};
template<int MOD>
class ModInt {
public:
    ModInt() :value(0) {}
    ModInt(long long val) :value((int)(val<0 ? MOD + val%MOD : val%MOD)) { }
    ModInt& operator+=(ModInt that) {
        value = value + that.value;
        if (value >= MOD)value -= MOD;
        return *this;
    }
    ModInt& operator-=(ModInt that) {
        value -= that.value;
        if (value<0)value += MOD;
        return *this;
    }
    ModInt& operator*=(ModInt that) {
        value = (int)((long long)value * that.value % 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 pow(long long k) const {
        if (value == 0)return 0;
        ModInt n = *this, res = 1;
        while (k) {
            if (k & 1)res *= n;
            n *= n;
            k >>= 1;
        }
        return res;
    }
    ModInt inverse() const {
        long long a = value, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        return ModInt(u);
    }
    int toi() const { return value; }
private:
    int value;
};
typedef ModInt<1000000007> mint;
ostream& operator<<(ostream& os, const mint& x) {
    os << x.toi();
    return os;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    string S;
    cin >> S;
    int N = sz(S);
    vector<mint> dp(N);
    dp[0] = 1;
    RollingHash rh = RollingHash(S);
    rep(i, N / 2) {
        for (int j = i + 1; j <= N / 2; ++j) {
            if (rh.getHash(i, j) == rh.getHash(N - j, N - i)) {
                dp[j] += dp[i];
            }
        }
    }
    mint ans = accumulate(all(dp), mint());
    cout << ans << endl;
}
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