結果

問題 No.269 見栄っ張りの募金活動
ユーザー Suu0313Suu0313
提出日時 2021-02-15 19:20:53
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 5 ms / 5,000 ms
コード長 2,284 bytes
コンパイル時間 2,509 ms
コンパイル使用メモリ 193,836 KB
最終ジャッジ日時 2025-01-18 21:13:02
ジャッジサーバーID
(参考情報)
judge1 / judge4
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

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 rep(i,n) for (int i = 0; i < (n); ++i)
using ll = long long;
using pii = pair<int,int>;
template< int mod >
struct ModInt {
int x;
ModInt() : x(0) {}
ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
ModInt &operator+=(const ModInt &p) {
if((x += p.x) >= mod) x -= mod;
return *this;
}
ModInt &operator-=(const ModInt &p) {
if((x += mod - p.x) >= mod) x -= mod;
return *this;
}
ModInt &operator*=(const ModInt &p) {
x = (int) (1LL * x * p.x % mod);
return *this;
}
ModInt &operator/=(const ModInt &p) {
*this *= p.inverse();
return *this;
}
ModInt operator-() const { return ModInt(-x); }
ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
bool operator==(const ModInt &p) const { return x == p.x; }
bool operator!=(const ModInt &p) const { return x != p.x; }
ModInt inverse() const {
int a = x, b = mod, u = 1, v = 0, t;
while(b > 0) {
t = a / b;
swap(a -= t * b, b);
swap(u -= t * v, v);
}
return ModInt(u);
}
ModInt pow(int64_t n) const {
ModInt ret(1), mul(x);
while(n > 0) {
if(n & 1) ret *= mul;
mul *= mul;
n >>= 1;
}
return ret;
}
friend ostream &operator<<(ostream &os, const ModInt &p) {
return os << p.x;
}
friend istream &operator>>(istream &is, ModInt &a) {
int64_t t;
is >> t;
a = ModInt< mod >(t);
return (is);
}
static int get_mod() { return mod; }
};
constexpr int MOD = 1e9 + 7;
using mint = ModInt< MOD >;
int main(){
int N, S, K; cin >> N >> S >> K;
/*
a0 + (a0+K + a1) + (a0+K+a1+K + a2) + ...
= (N-1)N/2 * K + Na0 + (N-1)a1 + ..
//*/
S -= (N-1)*N/2 * K;
if(S < 0){
cout << 0 << endl;
return 0;
}
vector dp(S+1, mint(1));
/*
dp_i+1,j = dp_i,j + dp_i,j-(n-i+1) + dp_i,j-2(n-i+1) + ...
= dp_i,j + dp_i+1,j-(n-i)
//*/
rep(i,N-1){
for(int j = N-i; j <= S; j++){
dp[j] += dp[j-(N-i)];
}
}
cout << dp[S] << endl;
}
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