将m=R−L带入公式可得:CR−L+1R−L+n+1−1
数据范围1e9,使用lucas计算即可,复杂度为PlogPN(log可被忽略)
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int p = 1000003;
int qsm(int a, int k)
{
int res = 1;
while (k)
{
if (k & 1) res = (ll)res * a % p;
a = (ll)a * a % p;
k >>= 1;
}
return res;
}
int C(int a,int b){
if(a<b) return 0;
int down = 1, up = 1; //up代表分子,down代表分母
for (int i = a, j = 1; j <= b; i --, j ++ )
{
up = (ll)up * i % p;
down = (ll)down * j % p;
}
return (ll)up * qsm(down, p - 2) % p;
}
int Lucas(int a,int b){
if(a<p&&b<p) return C(a,b)%p;
else return (ll)C(a%p,b%p)*Lucas(a/p,b/p)%p;
}
int main()
{
int T;
cin >> T;
while (T -- )
{
int n, l, r;
cin >> n >> l >> r;
cout << (Lucas(r - l + n + 1, r - l + 1) - 1 + p ) % p << endl;
}
return 0;
}