【HDU 3037】Saving Beans Lucas定理模板

http://acm.hdu.edu.cn/showproblem.php?pid=3037

Lucas定理模板。

现在才写，noip滚粗前兆QAQ

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
int jc[100003];
int p;

int ipow(int x, int b) {
	ll t = 1, w = x;
	while (b) {
		if (b & 1) t = t * w % p;
		w = w * w % p;
		b >>= 1;
	}
	return (int) t;
}

int Lucas(int n, int m) {
	int a, b, ret = 1;
	while (n && m) {
		a = n % p; b = m % p;
		if (a < b) return 0;
		ret = (int) (1ll * ret * jc[a] % p * ipow((int) (1ll * jc[a - b] * jc[b] % p), p - 2) % p);
		n /= p; m /= p;
	}
	return ret;
}

int main() {
	int T, n, m;
	scanf("%d", &T);
	while (T--) {
		scanf("%d%d%d", &n, &m, &p);
		jc[0] = 1;
		for (int i = 1; i < p; ++i)
			jc[i] = (int) (1ll * jc[i - 1] * i % p);
		printf("%d\n", Lucas(n + m, n));
	}
	return 0;
}