思路

AC代码

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 998244353;
ll quick_mod(ll a, ll b){
	ll sum = 1;
	while(b){
		if(b & 1) sum = sum * a % mod;
		a = a * a % mod;
		b /= 2;
	}
	return sum;
}
int main(){
   int t;
   scanf("%d", &t);
   while(t--){
	int m;
	ll ans = 1;
	scanf("%d", &m);
	while(m--){
		ll p, q;
		scanf("%lld%lld", &p, &q);
		ans = ans *  quick_mod(p, q - 1) % mod * (p + p * q % mod - q + mod) % mod;
	}
	printf("%lld\n", ans);
   }
   return 0;
}