#AT1868. H - Stroll
H - Stroll
H - Stroll
Score : $600$ points
Problem Statement
Takahashi has decided to wander around his house.
During his walk, he will roam between $N$ points called Point $1$, Point $2$, $\dots$, Point $N$, where Point $1$ is his house.
There are $M$ pairs of points connected by roads; let $(a_i, b_i)$ be the $i$-th of these pairs. There are $p_{i, d}$ roads with a length of $d$ $(1 \leq d \leq T)$ kilometers connecting Point $a_i$ and Point $b_i$.
Takahashi wants to know the number of $T$ kilometers courses that begin and end at his house. Here, a $T$ kilometers course is defined as follows.
- An alternating sequence with points and roads $v_0 = 1, e_0, v_1, \dots,e_{k-1}, v_k = 1$ such that $e_i$ $(0 \leq i \leq k-1)$ connects $v_i$ and $v_{i+1}$, and the total length of $e_i$ is $T$ kilometers.
Help Takahashi by finding the number of such courses modulo $998244353$. Two courses are considered different when they are different as sequences.
Constraints
- $2 \leq N \leq 10$
- $1 \leq M \leq \min \left(10, \frac{N(N-1)}{2} \right)$
- $1 \leq T \leq 4 \times 10^4$
- $1 \leq a_i \lt b_i \leq N$
- $(a_i, b_i) \neq (a_j, b_j)$ if $i \neq j$.
- $0 \leq p_{i,j} \lt 998244353$
Input
Input is given from Standard Input in the following format:
Output
Print the number of desirable courses, modulo $998244353$.
3 2 2
1 2
1 0
1 3
2 0
5
Around his house, there are:
- one $1$-kilometer road connecting Point $1$ and Point $2$, and
- two $1$-kilometer roads connecting Point $1$ and Point $3$.
We have the following five desirable courses:
- $1 \times 1 = 1$ course that goes Point $1$ $\to$ Point $2$ $\to$ Point $1$, and
- $2 \times 2 = 4$ courses that goes Point $1$ $\to$ Point $3$ $\to$ Point $1$.
3 3 4
1 2
3 0 0 0
1 3
0 1 0 0
2 3
2 0 0 0
130
Around his house, there are:
- three $1$-kilometer roads connecting Point $1$ and Point $2$,
- one $2$-kilometer road connecting Point $1$ and Point $3$, and
- two $1$-kilometer roads connecting Point $2$ and Point $3$.
The desirable courses can be classified into the following categories, according to the points visited:
- Point $1$ $\to$ Point $2$ $\to$ Point $1$ $\to$ Point $2$ $\to$ Point $1$,
- Point $1$ $\to$ Point $2$ $\to$ Point $3$ $\to$ Point $1$,
- Point $1$ $\to$ Point $2$ $\to$ Point $3$ $\to$ Point $2$ $\to$ Point $1$,
- Point $1$ $\to$ Point $3$ $\to$ Point $1$, and
- Point $1$ $\to$ Point $3$ $\to$ Point $2$ $\to$ Point $1$.
We have $81$, $6$, $36$, $1$, and $6$ course(s) of these categories, respectively.
2 1 5
1 2
31415 92653 58979 32384 62643
844557977