結果

問題 No.599 回文かい
ユーザー unagiunag
提出日時 2019-09-28 17:43:07
言語 C++14
(gcc 8.3.0)
結果
AC  
実行時間 117 ms
コード長 4,069 Byte
コンパイル時間 752 ms
使用メモリ 1,880 KB
最終ジャッジ日時 2019-09-28 17:43:10

テストケース

テストケース表示
入力 結果 実行時間
使用メモリ
0_0.txt AC 3 ms
1,524 KB
0_1.txt AC 3 ms
1,524 KB
0_2.txt AC 3 ms
1,528 KB
0_3.txt AC 3 ms
1,532 KB
1_0.txt AC 3 ms
1,556 KB
1_1.txt AC 3 ms
1,552 KB
1_2.txt AC 3 ms
1,560 KB
1_3.txt AC 3 ms
1,556 KB
1_4.txt AC 4 ms
1,556 KB
1_5.txt AC 3 ms
1,560 KB
2_0.txt AC 51 ms
1,752 KB
2_1.txt AC 32 ms
1,696 KB
2_2.txt AC 58 ms
1,772 KB
2_3.txt AC 35 ms
1,700 KB
2_4.txt AC 101 ms
1,844 KB
2_5.txt AC 117 ms
1,868 KB
2_6.txt AC 103 ms
1,864 KB
2_7.txt AC 117 ms
1,880 KB
3_0.txt AC 4 ms
1,548 KB
3_1.txt AC 3 ms
1,544 KB
3_2.txt AC 3 ms
1,540 KB
evil_0.txt AC 72 ms
1,784 KB
テストケース一括ダウンロード

ソースコード

diff #
#include <cassert>
#include <cstdio>
#include <cmath>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <numeric>
#include <algorithm>

using namespace std;
using lint = long long;
constexpr int MOD = 1000000007, INF = 1010101010;
constexpr lint LINF = 1LL << 60;

template <class T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
	for (const auto &e : vec) os << e << (&e == &vec.back() ? "" : " ");
	return os;
}

#ifdef _DEBUG
template <class T>
void dump(const char* str, T &&h) { cerr << str << " = " << h << "\n"; };
template <class Head, class... Tail>
void dump(const char* str, Head &&h, Tail &&... t) {
	while (*str != ',') cerr << *str++; cerr << " = " << h << "\n";
	dump(str + (*(str + 1) == ' ' ? 2 : 1), t...);
}
#define DMP(...) dump(#__VA_ARGS__, __VA_ARGS__)
#else 
#define DMP(...) ((void)0)
#endif

template<int Modulo> struct Mint {

	lint val;
	constexpr Mint(lint v = 0) noexcept : val(v % Modulo) { if (val < 0) v += Modulo; }

	constexpr Mint& operator += (const Mint &r) noexcept {
		val += r.val;
		if (val >= Modulo) val -= Modulo;
		return *this;
	}
	constexpr Mint& operator -= (const Mint &r) noexcept {
		val -= r.val;
		if (val < 0) val += Modulo;
		return *this;
	}
	constexpr Mint& operator *= (const Mint &r) noexcept {
		val = val * r.val % Modulo;
		return *this;
	}
	constexpr Mint& operator /= (const Mint &r) noexcept {
		lint a = r.val, b = Modulo, u = 1, v = 0;
		while (b) {
			lint t = a / b;
			a -= t * b; swap(a, b);
			u -= t * v; swap(u, v);
		}
		val = val * u % Modulo;
		if (val < 0) val += Modulo;
		return *this;
	}

	constexpr Mint operator + (const Mint &r) const noexcept { return Mint(*this) += r; }
	constexpr Mint operator - (const Mint &r) const noexcept { return Mint(*this) -= r; }
	constexpr Mint operator * (const Mint &r) const noexcept { return Mint(*this) *= r; }
	constexpr Mint operator / (const Mint &r) const noexcept { return Mint(*this) /= r; }

	constexpr int getmod() { return Modulo; }
	constexpr Mint operator - () const noexcept { return val ? Modulo - val : 0; }

	constexpr bool operator == (const Mint &r) const noexcept { return val == r.val; }
	constexpr bool operator != (const Mint &r) const noexcept { return val != r.val; }

	friend ostream &operator << (ostream &os, const Mint<Modulo> &x) noexcept { return os << x.val; }
	friend istream &operator >> (istream &is, Mint<Modulo> &x) noexcept {
		lint tmp; is >> tmp;
		x = Mint<Modulo>(tmp);
		return is;
	}
	friend constexpr Mint<Modulo> modpow(const Mint<Modulo> &a, lint n) noexcept {
		Mint res(1), tmp = a;
		while (n > 0) {
			if (n & 1) res *= tmp;
			tmp *= tmp;
			n >>= 1;
		}
		return res;
	}
};

//// mod, base from https://gist.github.com/privet-kitty/295ac9202b7abb3039b493f8238bf40f
class RollingHash {

private:
	using Mint1 = Mint<2147483647>;
	using Mint2 = Mint<2147483629>;

	vector<Mint1> hash1, pow1;
	vector<Mint2> hash2, pow2;
	const int base1 = 2147483634;
	const int base2 = 2147483627;
	int sz;

public:
	RollingHash() {}
	RollingHash(const string &s) :sz(s.size()) {

		hash1.assign(sz + 1, 0); pow1.assign(sz + 1, 1);
		hash2.assign(sz + 1, 0); pow2.assign(sz + 1, 1);

		for (int i = 0; i < sz; i++) {
			hash1[i + 1] = hash1[i] * base1 + s[i];
			pow1[i + 1] = pow1[i] * base1;
			hash2[i + 1] = hash2[i] * base2 + s[i];
			pow2[i + 1] = pow2[i] * base2;
		}
	}

	pair<int, int> get(int l, int r) {
		int res1 = (hash1[r] - hash1[l] * pow1[r - l]).val;
		int res2 = (hash2[r] - hash2[l] * pow2[r - l]).val;
		return { res1, res2 };
	}
};

int main() {

	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	string S; 
	cin >> S;
	int sz = S.size();
	RollingHash rh(S);

	using mint = Mint<MOD>;
	vector<mint> dp(sz / 2 + 1, 0);
	dp[0] = 1;
	for (int i = 1; i <= sz / 2; i++) {
		for (int j = 1; j <= i; j++) {
			if (rh.get(i - j, i) == rh.get(sz - i, sz - (i - j))) {
				dp[i] += dp[i - j];
			}
		}
	}

	mint ans = 0;
	for (int i = 0; i < sz / 2 + 1; i++)  ans += dp[i];
	cout << ans << "\n";

	return 0;
}
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