Submission #4564530


Source Code Expand

#include <cstdio>
#include <algorithm>

const int maxn = 1000005, P = 998244353;
int n, m, fac[maxn], ifac[maxn];

int power(int a, int x)
{
	int ans = 1;
	for (; x; x >>= 1, a = 1LL * a * a % P)
		if (x & 1)
			ans = 1LL * ans * a % P;
	return ans;
}
int binom(int n, int m)
{
	if (n < m || m < 0)
		return 0;
	return 1LL * fac[n] * ifac[m] % P * ifac[n - m] % P;
}

int main()
{
	scanf("%d%d", &n, &m);
	if (n < m)
		std::swap(n, m);
	fac[0] = 1;
	for (int i = 1; i <= n + m; ++i)
		fac[i] = 1LL * fac[i - 1] * i % P;
	ifac[n + m] = power(fac[n + m], P - 2);
	for (int i = n + m; i; --i)
		ifac[i - 1] = 1LL * ifac[i] * i % P;
	int ans = 0;
	for (int i = 1; i <= m; ++i)
		ans = (ans + 1LL * binom(2 * i, i) * binom(n + m - 2 * i, n - i)) % P;
	ans = 1LL * ans * power(2 * binom(n + m, n) % P, P - 2) % P;
	ans = (ans + n) % P;
	printf("%d\n", ans);
	return 0;
}

Submission Info

Submission Time
Task F - Yes or No
User luogu_bot5
Language C++14 (GCC 5.4.1)
Score 2000
Code Size 865 Byte
Status AC
Exec Time 18 ms
Memory 7936 KB

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:24:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
                       ^

Judge Result

Set Name Sample Partial All
Score / Max Score 0 / 0 1500 / 1500 500 / 500
Status
AC × 5
AC × 28
AC × 75
Set Name Test Cases
Sample sample_01.txt, sample_02.txt, sample_03.txt, sample_04.txt, sample_05.txt
Partial sample_01.txt, sample_02.txt, sample_04.txt, subtask_1_01.txt, subtask_1_02.txt, subtask_1_03.txt, subtask_1_04.txt, subtask_1_05.txt, subtask_1_06.txt, subtask_1_07.txt, subtask_1_08.txt, subtask_1_09.txt, subtask_1_10.txt, subtask_1_11.txt, subtask_1_12.txt, subtask_1_13.txt, subtask_1_14.txt, subtask_1_15.txt, subtask_1_16.txt, subtask_1_17.txt, subtask_1_18.txt, subtask_1_19.txt, subtask_1_20.txt, subtask_1_21.txt, subtask_1_22.txt, subtask_1_23.txt, subtask_1_24.txt, subtask_1_25.txt
All sample_01.txt, sample_02.txt, sample_03.txt, sample_04.txt, sample_05.txt, sample_01.txt, sample_02.txt, sample_03.txt, sample_04.txt, sample_05.txt, subtask_1_01.txt, subtask_1_02.txt, subtask_1_03.txt, subtask_1_04.txt, subtask_1_05.txt, subtask_1_06.txt, subtask_1_07.txt, subtask_1_08.txt, subtask_1_09.txt, subtask_1_10.txt, subtask_1_11.txt, subtask_1_12.txt, subtask_1_13.txt, subtask_1_14.txt, subtask_1_15.txt, subtask_1_16.txt, subtask_1_17.txt, subtask_1_18.txt, subtask_1_19.txt, subtask_1_20.txt, subtask_1_21.txt, subtask_1_22.txt, subtask_1_23.txt, subtask_1_24.txt, subtask_1_25.txt, subtask_2_01.txt, subtask_2_02.txt, subtask_2_03.txt, subtask_2_04.txt, subtask_2_05.txt, subtask_2_06.txt, subtask_2_07.txt, subtask_2_08.txt, subtask_2_09.txt, subtask_2_10.txt, subtask_2_11.txt, subtask_2_12.txt, subtask_2_13.txt, subtask_2_14.txt, subtask_2_15.txt, subtask_2_16.txt, subtask_2_17.txt, subtask_2_18.txt, subtask_2_19.txt, subtask_2_20.txt, subtask_2_21.txt, subtask_2_22.txt, subtask_2_23.txt, subtask_2_24.txt, subtask_2_25.txt, subtask_2_26.txt, subtask_2_27.txt, subtask_2_28.txt, subtask_2_29.txt, subtask_2_30.txt, subtask_2_31.txt, subtask_2_32.txt, subtask_2_33.txt, subtask_2_34.txt, subtask_2_35.txt, subtask_2_36.txt, subtask_2_37.txt, subtask_2_38.txt, subtask_2_39.txt, subtask_2_40.txt
Case Name Status Exec Time Memory
sample_01.txt AC 1 ms 2176 KB
sample_02.txt AC 1 ms 2176 KB
sample_03.txt AC 1 ms 2176 KB
sample_04.txt AC 1 ms 2176 KB
sample_05.txt AC 1 ms 2176 KB
subtask_1_01.txt AC 1 ms 2176 KB
subtask_1_02.txt AC 1 ms 2176 KB
subtask_1_03.txt AC 1 ms 2176 KB
subtask_1_04.txt AC 1 ms 2176 KB
subtask_1_05.txt AC 1 ms 2176 KB
subtask_1_06.txt AC 1 ms 2176 KB
subtask_1_07.txt AC 1 ms 2176 KB
subtask_1_08.txt AC 1 ms 2176 KB
subtask_1_09.txt AC 1 ms 2176 KB
subtask_1_10.txt AC 1 ms 2176 KB
subtask_1_11.txt AC 1 ms 2176 KB
subtask_1_12.txt AC 1 ms 2176 KB
subtask_1_13.txt AC 1 ms 2304 KB
subtask_1_14.txt AC 3 ms 4480 KB
subtask_1_15.txt AC 5 ms 4992 KB
subtask_1_16.txt AC 5 ms 4992 KB
subtask_1_17.txt AC 5 ms 4992 KB
subtask_1_18.txt AC 5 ms 4992 KB
subtask_1_19.txt AC 5 ms 4992 KB
subtask_1_20.txt AC 5 ms 4992 KB
subtask_1_21.txt AC 5 ms 4992 KB
subtask_1_22.txt AC 5 ms 4992 KB
subtask_1_23.txt AC 5 ms 4992 KB
subtask_1_24.txt AC 5 ms 4992 KB
subtask_1_25.txt AC 4 ms 4992 KB
subtask_2_01.txt AC 1 ms 2176 KB
subtask_2_02.txt AC 1 ms 2176 KB
subtask_2_03.txt AC 1 ms 2176 KB
subtask_2_04.txt AC 18 ms 7936 KB
subtask_2_05.txt AC 18 ms 7936 KB
subtask_2_06.txt AC 18 ms 7936 KB
subtask_2_07.txt AC 18 ms 7936 KB
subtask_2_08.txt AC 18 ms 7936 KB
subtask_2_09.txt AC 18 ms 7936 KB
subtask_2_10.txt AC 18 ms 7936 KB
subtask_2_11.txt AC 18 ms 7936 KB
subtask_2_12.txt AC 18 ms 7936 KB
subtask_2_13.txt AC 18 ms 7936 KB
subtask_2_14.txt AC 18 ms 7936 KB
subtask_2_15.txt AC 18 ms 7936 KB
subtask_2_16.txt AC 18 ms 7936 KB
subtask_2_17.txt AC 18 ms 7936 KB
subtask_2_18.txt AC 17 ms 7680 KB
subtask_2_19.txt AC 15 ms 7168 KB
subtask_2_20.txt AC 7 ms 6272 KB
subtask_2_21.txt AC 7 ms 6272 KB
subtask_2_22.txt AC 7 ms 6272 KB
subtask_2_23.txt AC 7 ms 6272 KB
subtask_2_24.txt AC 7 ms 6272 KB
subtask_2_25.txt AC 7 ms 6272 KB
subtask_2_26.txt AC 7 ms 6272 KB
subtask_2_27.txt AC 7 ms 6272 KB
subtask_2_28.txt AC 7 ms 6272 KB
subtask_2_29.txt AC 7 ms 6272 KB
subtask_2_30.txt AC 9 ms 6400 KB
subtask_2_31.txt AC 12 ms 6784 KB
subtask_2_32.txt AC 18 ms 7936 KB
subtask_2_33.txt AC 18 ms 7936 KB
subtask_2_34.txt AC 18 ms 7936 KB
subtask_2_35.txt AC 18 ms 7936 KB
subtask_2_36.txt AC 18 ms 7936 KB
subtask_2_37.txt AC 9 ms 6144 KB
subtask_2_38.txt AC 6 ms 5888 KB
subtask_2_39.txt AC 17 ms 7808 KB
subtask_2_40.txt AC 9 ms 6400 KB