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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#775034#9553. The HermitTangWKWA 54ms15788kbC++201.9kb2024-11-23 14:33:102024-11-23 14:33:19

Judging History

你现在查看的是最新测评结果

  • [2024-11-23 14:33:19]
  • 评测
  • 测评结果:WA
  • 用时:54ms
  • 内存:15788kb
  • [2024-11-23 14:33:10]
  • 提交

answer

#include <bits/stdc++.h>
const int mod = 998244353;
void solve() {
	int m, n;
	std::cin >> m >> n;

	auto q_pow = [&] (int x, int p, int mod) {
		int ret = 1;
		while(p) {
			if(p & 1) {
				ret = (1ll * ret * x) % mod;
			}
			x = (1ll * x * x) % mod;
			p >>= 1;
		}
		return ret;
	};
	std::vector<int> fac(m + 1);
	std::vector<int> inv_fac(m + 1);
	fac[0] = 1;
	for (int i = 1; i <= m; ++i) {
		fac[i] = (1ll * fac[i - 1] * i) % mod;
	}
	inv_fac[m] = q_pow(fac[m], mod - 2, mod);
	for (int i = m; i >= 1; --i) {
		inv_fac[i - 1] = (1ll * inv_fac[i] * i) % mod;
	}
	auto C = [&] (int n, int m) {
		if(n < m) {
			// return 0ll;
			return 0ll;
		}
		int tmp_up = fac[n];
		int tmp_down = (1ll * inv_fac[m] * inv_fac[n - m]) % mod;
		return (1ll * tmp_up * tmp_down) % mod;
	};

	std::vector<std::vector<int>> dp(m + 1, std::vector<int>(20));
	for (int i = 1; i <= m; ++i) {
		dp[i][1] = 1;
		for (int j = 1; j * j <= i && j < i; ++j) {
			if(i % j == 0) {
				int tmp = i / j;
				for (int k = 2; k <= 20; ++k) {
					if (dp[j][k - 1] > 0) {
						dp[i][k] += dp[j][k - 1];
					}else {
						break;
					}
				}
				if (tmp > j && tmp < i) {
					for (int k = 2; k <= 20; ++k) {
						if (dp[tmp][k - 1] > 0) {
							dp[i][k] += dp[tmp][k - 1];
						}else {
							break;
						}
					}
				}
			}
		}
	}
	int ans = (1ll * n * C(m, n)) % mod;
	for (int i = 1; i <= m; ++i) {
		int tmp = 0;
		for (int k = 1; k <= 20; ++k) {
			if (dp[i][k] <= 0) {
				break;
			}
			// printf("{%d, %d} = %d\n", i, k, dp[i][k]);
			tmp = (0ll + tmp + 1ll * dp[i][k] * C(m / i - 1, n - k)) % mod;
		}
		// printf("tmp = %d, ans = %d\n", tmp, ans);
		ans = (0ll + mod + ans - tmp) % mod;
	}
	std::cout << ans << "\n";
	return;
}
int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int t = 1;
	// std::cin >> t;
	while(t--) {
		solve();
	}
	return 0;
}

詳細信息

Test #1:

score: 100
Accepted
time: 0ms
memory: 3644kb

input:

4 3

output:

7

result:

ok 1 number(s): "7"

Test #2:

score: 0
Accepted
time: 0ms
memory: 3828kb

input:

11 4

output:

1187

result:

ok 1 number(s): "1187"

Test #3:

score: 0
Accepted
time: 53ms
memory: 15700kb

input:

100000 99999

output:

17356471

result:

ok 1 number(s): "17356471"

Test #4:

score: 0
Accepted
time: 0ms
memory: 4784kb

input:

11451 1919

output:

845616153

result:

ok 1 number(s): "845616153"

Test #5:

score: 0
Accepted
time: 52ms
memory: 15764kb

input:

99998 12345

output:

936396560

result:

ok 1 number(s): "936396560"

Test #6:

score: -100
Wrong Answer
time: 54ms
memory: 15788kb

input:

100000 1

output:

101288180

result:

wrong answer 1st numbers differ - expected: '0', found: '101288180'