提出 #7121477


ソースコード 拡げる

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#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
//#pragma GCC optimize ("-O3")
using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); }
typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60;
template<class T>bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
//---------------------------------------------------------------------------------------------------
template<int MOD> struct ModInt {
    static const int Mod = MOD; unsigned x; ModInt() : x(0) { }
    ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    int get() const { return (int)x; }
    ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % 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 inverse() const { long long a = x, b = MOD, u = 1, v = 0;
        while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); }
        return ModInt(u); }
    bool operator==(ModInt that) const { return x == that.x; }
    bool operator!=(ModInt that) const { return x != that.x; }
    ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; }
};
template<int MOD> ostream& operator<<(ostream& st, const ModInt<MOD> a) { st << a.get(); return st; };
template<int MOD> ModInt<MOD> operator^(ModInt<MOD> a, unsigned long long k) {
    ModInt<MOD> r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; }
typedef ModInt<1000000007> mint;
template<class V> struct BIT {
    BIT() {}  // [L, R)
    int NV;vector<V> bit;
    BIT(int n){ init(n); }
    void init(int n) { NV = 1; while (NV < n)NV *= 2; bit.resize(NV); clear(); }
    V operator[](int e) { V s = 0; e++; while (e) s += bit[e - 1], e -= e&-e; return s; }
    void add(int e, V v) { e++; while (e <= NV) bit[e - 1] += v, e += e&-e; }
    int lower_bound(V val) { 
        V tv = 0; int i, ent = 0; for (i = NV - 1; i >= 0; i--)
        if(tv+bit[ent+(1<<i)-1]<=val)tv+=bit[ent+(1<<i)-1],ent += (1 << i);return ent;
    }
    V get(int L, int R) {
        assert(0 <= L); assert(R <= NV); assert(L <= R);
        V res = 0; if(R) res += operator[](R - 1); if (L) res -= operator[](L - 1);return res;
    }
    void clear() { rep(i, 0, NV) bit[i] = 0; }
	void update(int e, V v) { add(e, v - get(e, e + 1)); }
};
/*---------------------------------------------------------------------------------------------------
            ∧_∧
      ∧_∧  (´<_` )  Welcome to My Coding Space!
     ( ´_ゝ`) /  ⌒i     @hamayanhamayan
    /   \     | |
    /   / ̄ ̄ ̄ ̄/  |
  __(__ニつ/     _/ .| .|____
     \/____/ (u ⊃
---------------------------------------------------------------------------------------------------*/














int N, K, A[2010];
BIT<int> bit(2010);
//---------------------------------------------------------------------------------------------------
void _main() {
    cin >> N >> K;
    rep(i, 0, N) cin >> A[i];

    mint tot1 = 0;
    rep(i, 0, N) {
        tot1 += bit.get(A[i] + 1, 2010);
        bit.add(A[i], 1);
    }

    mint tot2 = 0;
    rep(i, 0, N) tot2 += bit.get(A[i] + 1, 2010);

    mint ans = tot1 * K + mint(K) * mint(K - 1) / 2 * tot2;
    cout << ans << endl;
}





提出情報

提出日時
問題 B - Kleene Inversion
ユーザ hamayanhamayan
言語 C++14 (GCC 5.4.1)
得点 300
コード長 4201 Byte
結果
実行時間 1 ms
メモリ 256 KB

テストケース

セット名 得点 / 配点 テストケース
All 300 / 300 sample_01, sample_02, sample_03, testcase_0, testcase_1, testcase_10, testcase_11, testcase_12, testcase_13, testcase_14, testcase_15, testcase_16, testcase_17, testcase_18, testcase_19, testcase_2, testcase_20, testcase_3, testcase_4, testcase_5, testcase_6, testcase_7, testcase_8, testcase_9
Sample 0 / 0 sample_01, sample_02, sample_03
ケース名 結果 実行時間 メモリ
sample_01 1 ms 256 KB
sample_02 1 ms 256 KB
sample_03 1 ms 256 KB
testcase_0 1 ms 256 KB
testcase_1 1 ms 256 KB
testcase_10 1 ms 256 KB
testcase_11 1 ms 256 KB
testcase_12 1 ms 256 KB
testcase_13 1 ms 256 KB
testcase_14 1 ms 256 KB
testcase_15 1 ms 256 KB
testcase_16 1 ms 256 KB
testcase_17 1 ms 256 KB
testcase_18 1 ms 256 KB
testcase_19 1 ms 256 KB
testcase_2 1 ms 256 KB
testcase_20 1 ms 256 KB
testcase_3 1 ms 256 KB
testcase_4 1 ms 256 KB
testcase_5 1 ms 256 KB
testcase_6 1 ms 256 KB
testcase_7 1 ms 256 KB
testcase_8 1 ms 256 KB
testcase_9 1 ms 256 KB