結果

問題 No.1102 Remnants
ユーザー firiexpfiriexp
提出日時 2020-07-03 22:18:03
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 58 ms / 2,000 ms
コード長 2,994 bytes
コンパイル時間 1,069 ms
コンパイル使用メモリ 106,748 KB
実行使用メモリ 4,964 KB
最終ジャッジ日時 2023-10-17 04:23:14
合計ジャッジ時間 2,791 ms
ジャッジサーバーID
(参考情報)
judge15 / judge14
このコードへのチャレンジ(β)

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
4,348 KB
testcase_01 AC 2 ms
4,348 KB
testcase_02 AC 2 ms
4,348 KB
testcase_03 AC 2 ms
4,348 KB
testcase_04 AC 1 ms
4,348 KB
testcase_05 AC 43 ms
4,700 KB
testcase_06 AC 10 ms
4,348 KB
testcase_07 AC 58 ms
4,964 KB
testcase_08 AC 3 ms
4,348 KB
testcase_09 AC 4 ms
4,348 KB
testcase_10 AC 2 ms
4,348 KB
testcase_11 AC 3 ms
4,348 KB
testcase_12 AC 4 ms
4,348 KB
testcase_13 AC 4 ms
4,348 KB
testcase_14 AC 26 ms
4,348 KB
testcase_15 AC 21 ms
4,348 KB
testcase_16 AC 51 ms
4,700 KB
testcase_17 AC 48 ms
4,700 KB
testcase_18 AC 51 ms
4,700 KB
testcase_19 AC 18 ms
4,348 KB
testcase_20 AC 7 ms
4,348 KB
testcase_21 AC 31 ms
4,348 KB
testcase_22 AC 43 ms
4,436 KB
testcase_23 AC 34 ms
4,348 KB
testcase_24 AC 25 ms
4,348 KB
testcase_25 AC 51 ms
4,700 KB
testcase_26 AC 5 ms
4,348 KB
testcase_27 AC 15 ms
4,348 KB
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 <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

template<u32 M = 1000000007>
struct modint{
    u32 val;
    modint(): val(0){}
    template<typename T>
    modint(T t){t %= (T)M; if(t < 0) t += (T)M; val = t;}

    modint pow(ll k) const {
        modint res(1), x(val);
        while(k){
            if(k&1) res *= x;
            x *= x;
            k >>= 1;
        }
        return res;
    }
    template<typename T>
    modint& operator=(T t){t %= (T)M; if(t < 0) t += (T)M; val = t; return *this;}
    modint inv() const {return pow(M-2);}
    modint& operator+=(modint a){val += a.val; if(val >= M) val -= M; return *this;}
    modint& operator-=(modint a){if(val < a.val) val += M-a.val; else val -= a.val; return *this;}
    modint& operator*=(modint a){val = (u64)val*a.val%M; return *this;}
    modint& operator/=(modint a){return (*this) *= a.inv();}
    modint operator+(modint a) const {return modint(val) +=a;}
    modint operator-(modint a) const {return modint(val) -=a;}
    modint operator*(modint a) const {return modint(val) *=a;}
    modint operator/(modint a) const {return modint(val) /=a;}
    modint operator-(){return modint(M-val);}
    bool operator==(const modint a) const {return val == a.val;}
    bool operator!=(const modint a) const {return val != a.val;}
    bool operator<(const modint a) const {return val < a.val;}
};
using mint = modint<MOD>;

class Factorial {
    vector<mint> facts, factinv;
public:
    explicit Factorial(int n) : facts(n+1), factinv(n+1) {
        facts[0] = 1;
        for (int i = 1; i < n+1; ++i) facts[i] = facts[i-1] * mint(i);
        factinv[n] = facts[n].inv();
        for (int i = n-1; i >= 0; --i) factinv[i] = factinv[i+1] * mint(i+1);
    }
    mint fact(int k) const {
        if(k >= 0) return facts[k]; else return factinv[-k];
    }
    mint operator[](const int &k) const {
        if(k >= 0) return facts[k]; else return factinv[-k];
    }
    mint C(int p, int q) const {
        if(q < 0 || p < q) return 0;
        return facts[p] * factinv[q] * factinv[p-q];
    }
    mint P(int p, int q) const {
        if(q < 0 || p < q) return 0;
        return facts[p] * factinv[p-q];
    }
    mint H(int p, int q) const {
        if(p < 0 || q < 0) return 0;
        return q == 0 ? 1 : C(p+q-1, q);
    }
};

int main() {
    int n, k;
    cin >> n >> k;
    vector<int> v(n);
    for (auto &&i : v) scanf("%d", &i);
    vector<mint> dp(n+1);
    dp[0] = 1;
    for (int i = 1; i <= n; ++i) {
        dp[i] = dp[i-1]*mint(k+i)*(mint(i).inv());
    }
    mint ans = 0;
    for (int i = 0; i < n; ++i) {
        ans += mint(v[i])*dp[i]*dp[n-i-1];
    }
    cout << ans.val << "\n";
    return 0;
}
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