C++ 代码
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 1e6 + 10;
const int MOD = 998244353;
int f[N];
int qmi(int a, int k, int p)
{
LL res = 1;
while (k)
{
if (k & 1)res = res * a % p;
k >>= 1;
a = (LL)a * a % p;
}
return res;
}
int main()
{
int n; cin >> n;
f[0] = 0;
for (int i = 1; i <= n; i++)
{
int x, y; scanf("%d%d", &x, &y);
f[i] = (LL)(f[i-1]+1) * y % MOD * qmi(y - x,MOD-2,MOD) % MOD;
}
cout << f[n] << endl;
}
?这里不是小凸玩矩阵的题解区吗?