#P9847. Expectation (Easy Version)
Expectation (Easy Version)
Expectation (Easy Version)
Problem Description
Note: The only difference between the easy and hard versions is the range of and . You are to play a game for times. Each time you have the probability to win. If you win, you will get score, where is the total times you win at that time, otherwise you won't get any score. Your final score is the sum of the score you get each time. For instance, if , and you win twice in total, your final score is . Now you wonder the expectation of your final score modulo .
Input
The first line of the input contains an integer , indicating the number of the test cases. The next lines, each line has four integers $n, m, a, b\ (1\le n\le 10^6, 1 \le m,a,b < 998244353)$, indicating the number of games you play, the power of is , and the probatility to win a game is . It's guaranteed that .
Output
lines, each line has one interger, indicating the answer.
Sample Input
4
3 1 1 2
3 2 1 2
3 3 1 2
114514 1000000 123456789 987654321
Sample Output
748683267
4
748683273
733239168
Hint
In first three test cases, you have the probability of to win once, to win twice, to win three times. The expectation of your final score is $\frac 38\times 1^m+\frac 38\times(1^m+2^m)+\frac 18\times(1^m+2^m+3^m)$. So your first three answers are .
Source
2023“钉耙编程”中国大学生算法设计超级联赛(5)