rt

#include<bits/stdc++.h>
#define int long long
using namespace std;
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int T;
	cin >> T;
	while(T--){
		int x,a,b;
		cin >> x >> a >> b;
		int minn = x;
		if((1 - a) * x + b <= 0){
			cout << x << '\n';
			continue;
		}
		if(a == 1 && b == 1){
			cout << -b << '\n';
			continue;
		}
		if(a == 1 && b == 2){
			cout << ((x & 1)?-1:-2) << '\n';
			continue;
		}
		for(;x>=0;){
			if(a * x - b >= x || x < 0) break;
			x = a * x - b;
			minn = min(minn,x);
		}
		cout << minn << '\n';
	}
}

以下代码的$a=1$的情况是判断不完全的，但是过了。