結果

問題 No.1343 Dividing Digit
コンテスト
ユーザー tkmst201
提出日時 2021-01-17 11:16:31
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 15 ms / 2,000 ms
コード長 4,109 bytes
コンパイル時間 1,795 ms
コンパイル使用メモリ 194,108 KB
最終ジャッジ日時 2025-01-18 00:01:44
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 22
権限があれば一括ダウンロードができます
コンパイルメッセージ
main.cpp: In function ‘int main()’:
main.cpp:79:24: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   79 |         REP(i, N) scanf("%d", &A[i]);
      |                   ~~~~~^~~~~~~~~~~~~

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

template<int ID>
struct RuntimeModInt {
public:
	using value_type = int;
	using calc_type = std::int_fast64_t;
	
private:
	value_type val_;
	static int & mod_() noexcept { static int M = 2; return M; }
	
public:
	RuntimeModInt(calc_type val = 0) : val_(val < 0 ? (val % mod() + mod()) % mod() : val % mod()) {}
	const value_type & val() const noexcept { return val_; }
	static void set_mod(int M) noexcept { assert(M > 0); mod_() = M; }
	static int mod() noexcept { return mod_(); }
	
	explicit operator bool() const noexcept { return val_; }
	bool operator !() const noexcept { return !static_cast<bool>(*this); }
	RuntimeModInt operator +() const noexcept { return RuntimeModInt(*this); }
	RuntimeModInt operator -() const noexcept { return RuntimeModInt(-val_); }
	RuntimeModInt operator ++(int) noexcept { RuntimeModInt res = *this; ++*this; return res; }
	RuntimeModInt operator --(int) noexcept { RuntimeModInt res = *this; --*this; return res; }
	RuntimeModInt & operator ++() noexcept { val_ = val_ + 1 == mod() ? 0 : val_ + 1; return *this; }
	RuntimeModInt & operator --() noexcept { val_ = val_ == 0 ? mod() - 1 : val_ - 1; return *this; }
	RuntimeModInt & operator +=(const RuntimeModInt & rhs) noexcept { val_ += val_ < mod() - rhs.val_ ? rhs.val_ : rhs.val_ - mod(); return *this; }
	RuntimeModInt & operator -=(const RuntimeModInt & rhs) noexcept { val_ += val_ >= rhs.val_ ? -rhs.val_ : mod() - rhs.val_; return *this; }
	RuntimeModInt & operator *=(const RuntimeModInt & rhs) noexcept { val_ = static_cast<calc_type>(val_) * rhs.val_ % mod(); return *this; }
	RuntimeModInt & operator /=(const RuntimeModInt & rhs) noexcept { return *this *= rhs.inv(); }
	friend RuntimeModInt operator +(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return RuntimeModInt(lhs) += rhs; }
	friend RuntimeModInt operator -(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return RuntimeModInt(lhs) -= rhs; }
	friend RuntimeModInt operator *(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return RuntimeModInt(lhs) *= rhs; }
	friend RuntimeModInt operator /(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return RuntimeModInt(lhs) /= rhs; }
	friend bool operator ==(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return lhs.val_ == rhs.val_; }
	friend bool operator !=(const RuntimeModInt & lhs, const RuntimeModInt & rhs) noexcept { return !(lhs == rhs); }
	friend std::ostream & operator <<(std::ostream & os, const RuntimeModInt & rhs) { return os << rhs.val_; }
	friend std::istream & operator >>(std::istream & is, RuntimeModInt & rhs) { calc_type x; is >> x; rhs = RuntimeModInt(x); return is; }
	
	RuntimeModInt pow(calc_type n) const noexcept {
		RuntimeModInt res = 1, x = val_;
		if (n < 0) { x = x.inv(); n = -n; }
		while (n) { if (n & 1) res *= x; x *= x; n >>= 1; }
		return res;
	}
	
	RuntimeModInt inv() const noexcept {
		value_type a = val_, a1 = 1, a2 = 0, b = mod(), b1 = 0, b2 = 1;
		while (b > 0) {
			value_type q = a / b, r = a % b;
			value_type nb1 = a1 - q * b1, nb2 = a2 - q * b2;
			a = b; b = r;
			a1 = b1; b1 = nb1;
			a2 = b2; b2 = nb2;
		}
		assert(a == 1);
		return a1;
	}
};
using mint = RuntimeModInt<-1>;

int main() {
	int N, K;
	cin >> N >> K;
	vector<int> A(N);
	REP(i, N) scanf("%d", &A[i]);
	int sum = accumulate(ALL(A), 0);
	mint::set_mod(sum);
	mint base = 1;
	mint ans = 0;
	for (int i = N - 1; i >= 0; --i) {
		ans += A[i] * base;
		base *= K;
	}
	cout << ans << endl;
}
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