P5702 Harmonic Series Summation
Description
Given $n, p$, find the value of:
$$\sum_{i=1}^n \frac 1i $$
modulo $p$.
If you do not know how to take a fraction modulo a number, you can refer to [this problem](https://www.luogu.com.cn/problem/P2613).
It is guaranteed that the answer exists modulo $p$.
To make your computation easier, the smallest primitive root $g$ of $p$ will be provided.
Input Format
The first line contains a positive integer $T$, the number of test cases.
The next $T$ lines each contain three positive integers $n, p, g$.
Output Format
Output $T$ lines. Each line contains one integer, the answer.
Explanation/Hint
Constraints
For $30\%$ of the testdata, $1\le n \le 10^6$.
For $100\%$ of the testdata, $1 \le n < p < 2^{30}$, $1\le T \le 20$.
It is guaranteed that $p$ is prime, and $p-1$ is divisible by $2^{19}$.
Note: The time limit is three times that of std. If you cannot pass, please check that your time complexity is correct and optimize the constant factors.
Translated by ChatGPT 5