Submission #19789

#	Time	Username	Problem	Language	Result	Execution time	Memory
19789		xhae	창문 (kriii4_C)	C++14	3 / 100	0 ms	1084 KiB

C

#include <cstdio>

const long long MOD = 1000000007;

long long inv(long long tar) {
	long long ret = 1;
	for(int i = 30; i >= 0; i--) {
		ret = ret * ret % MOD;
		if((1ll << i) & (MOD - 2)) ret = ret * tar % MOD;
	}

	return ret;
}

long long func(long long c, long long x) {
	long long ret = (x * x % MOD * x % MOD * inv(3) % MOD * -1 + MOD) % MOD;
	ret = (ret + x * x % MOD * c % MOD * inv(2) % MOD) % MOD;
	ret = (ret + c * inv(2) % MOD * x % MOD + x * inv(3) % MOD) % MOD;
	return ret;
}

int main(void) {
	long long h, w;
	scanf("%lld %lld", &h, &w);

	h %= MOD;
	w %= MOD;

	long long xsum = func(w, w);
	long long ysum = func(h, h);

	long long ans = xsum * ysum % MOD * 9 % MOD;
	long long cases = w * (w + 1) % MOD * inv(2) % MOD;
	cases = cases * (h * (h + 1) % MOD * inv(2) % MOD) % MOD;
	ans = ans * inv(cases) % MOD;
	printf("%lld\n", ans);

	return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 0 / 97