BZOJ 4403 2982 Lucas定理模板

思路：

Lucas定理的模板题..

4403

//By SiriusRen
#include <cstdio>
using namespace std;
const int mod=;
#define int long long
int cases,N,L,R,fac[mod],inv[mod];
int C(int n,int m){
    if(n<m)return ;
    if(n<mod&&m<mod)return fac[n]*inv[n-m]%mod*inv[m]%mod;
    return C(n/mod,m/mod)*C(n%mod,m%mod)%mod;
}
signed main(){
    fac[]=inv[]=inv[]=;
    for(int i=;i<mod;i++)fac[i]=fac[i-]*i%mod;
    for(int i=;i<mod;i++)inv[i]=(mod-mod/i)*inv[mod%i]%mod;
    for(int i=;i<mod;i++)inv[i]=inv[i-]*inv[i]%mod;
    scanf("%lld",&cases);
    while(cases--)scanf("%lld%lld%lld",&N,&L,&R),printf("%lld\n",(C(N+R-L+,R-L+)-+mod)%mod);
}

2982

//By SiriusRen
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define int long long
const int p=;
int fac[p],inv[p],n,m,cases;
int C(int i,int j){
    if(i<j)return ;
    if(i<p&&j<p)return fac[i]*inv[j]%p*inv[i-j]%p;
    return C(i/p,j/p)*C(i%p,j%p)%p;
}
signed main(){
    fac[]=fac[]=inv[]=inv[]=;
    for(int i=;i<p;i++)fac[i]=fac[i-]*i%p;
    for(int i=;i<p;i++)inv[i]=(p-p/i)*inv[p%i]%p;
    for(int i=;i<p;i++)inv[i]=inv[i-]*inv[i]%p;
    scanf("%lld",&cases);
    while(cases--){
        scanf("%lld%lld",&n,&m);
        printf("%lld\n",C(n,m));
    }
}