[组合数学] BZOJ 4403 序列统计

#include<cstdio>
#include<cstdlib>
using namespace std;
typedef long long ll;

inline char nc()
{
static char buf[100000],*p1=buf,*p2=buf;
if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }
return *p1++;
}

inline void read(ll &x)
{
char c=nc(),b=1;
for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}

const ll P=1000003;

ll fac[P+10],inv[P+10];

inline void Pre()
{
fac[0]=1;
for (int i=1;i<P;i++)
fac[i]=fac[i-1]*i%P;
inv[1]=1;
for (int i=2;i<P;i++)
inv[i]=(P-P/i)*inv[P%i]%P;
inv[0]=1;
for (int i=1;i<P;i++)
(inv[i]*=inv[i-1])%=P;
}

inline ll C(ll n,ll m)
{
if (m>n) return 0LL;
if (n<P && m<P)
return fac
*inv[m]%P*inv[n-m]%P;
return C(n/P,m/P)*C(n%P,m%P)%P;
}

int main()
{
Pre();
ll Q,n,m,l,r;
freopen("t.in","r",stdin);
freopen("t.out","w",stdout);
read(Q);
while (Q--)
{
read(n); read(l); read(r);
m=r-l+1;
printf("%lld\n",(C(n+m,n)-1+P)%P);
}
return 0;
}