Quick Notes

激励

每当在书中读及那些卑微的努力，都觉得感动且受震撼。也许每个人在发出属于自己的光芒之前，都经历了无数的煎熬，漫长的黑夜，无尽的孤独，甚至不断的嘲讽和否定，但好在那些踮脚的少年，最后都得到了自己想要的一切。

link

https://me.csdn.net/sz_165394732

https://www.luogu.org/discuss/show/82076

compare

int jc[mod], ijc[mod];

inline int qpow(int x, int y) {
    int r=1;
    for (; y; y>>=1, x=x*x%mod) if (y&1) r=r*x%mod;
    return r;
}
inline void init() {
    jc[0]=1; for (int i=1; i<mod; ++i) jc[i]=jc[i-1]*i%mod;
    ijc[mod-1]=qpow(jc[mod-1], mod-2);
    for (int i=mod-2; i>=0; --i) ijc[i]=ijc[i+1]*(i+1)%mod;
}
inline int C(int x, int y) {return jc[x]*(ijc[x-y]*ijc[y]%mod)%mod; }

inline int lucas(int x, int y) {
	if (y>x) return 0;
	int r=1;
	for (; y; x/=mod, y/=mod) r=r*C(x%mod, y%mod);
	return r;
}

int T, n, m;

int main() {
	init();
	scanf("%d", &T);
	while (T--) {
		scanf("%d%d", &n, &m);
		printf("%d\n", lucas(n, m));
	}
	return 0;
}

---

int jc[mod], inv[mod], t, n, m;

inline int lucas(int a, int b) {
	if (a > b) return 0;
	if (b <= mod) return jc[b] * inv[a] % mod * inv[b - a] % mod;
	return lucas(a / mod, b / mod) * lucas(a % mod, b % mod) % mod;
}

int main(void) {
	jc[0] = jc[1] = inv[0] = inv[1] = 1;
	for (int i = 2; i < mod; ++i) jc[i] = jc[i - 1] * i % mod, inv[i] = (mod - mod / i) * inv[mod % i] % mod;
	for (int i = 2; i < mod; ++i) inv[i] = inv[i - 1] * inv[i] % mod;
	for (scanf("%d", &t); t; --t) scanf("%d%d", &n, &m), printf("%d\n", lucas(m, n));
	return 0;
}

ぼくのフレンド (Boku no Friend)

aienkien ichigoichie

sode suriau mo tashou no en

kono yo no kiseki gyutto tsumete

kimi to deaetanda

aoi haru itsuka maku o toji

sakura to tomo ni maichittemo

kanarazu bokura mata dokoka de

deai o hatasu darou

kakegae nai

boku to nita kimi e

hitori de koronde kizu darake ni natta toki wa

itsudemo dokomademo hashiru yo

tama ni wa kenka shite okorou

nakigao mitara nagusameyou

tobikiri no nagai o sekkyou wa mijikame ni shite

kirei na mono o sagashi ni yukou

oishii mono mo takusan tabeyou

tsumari wa korekara mo douka yoroshiku ne

toki ga tatsu no wa hayai mono de

wakare no kisetsu ga kao o dasu

tsumiagetekita mono ga yake ni

namida o sasounda

aoi haru ga ima maku o toji

sakura ga chiru oto wa shizuka de

setsunai omoi ga oshiyoseta

sayonara no yuuyake

kakegae nai

boku to nita kimi wa

hitori demo daijoubu dakara tada mae o mite

hirogaru michi o hashirunda

tama ni wa futari katariaou

iya na koto zenbu hakidasou

tobikiri no nagai adobaisu wa chanto kiitete

ureshii koto wa houkoku shiyou

atarashii deai daiji ni shiyou

tsumari wa itsudemo itsumademo?

aa bokura wa tatta ima

gooru wa betsubetsu sutaato rain

omoide shimaikonde

fumidashita saki wa mirai e

kakegae nai

boku to nita kimi wa

hitori demo daijoubu dakara tada mae o mite

hirogaru michi o hashirunda

tama ni wa hodohodo ni yasumou

yasumetara yururi to susumou

tobikiri nagai kinkyou houkoku omachi shitemasu

doredake teki o tsukurou tomo

boku ga kimi no mikata de iru kara

tsumari wa korekara mo douka yoroshiku ne