Problem Statement
We have a grid with ~H~ rows and ~W~ columns of squares. Let ~(i, j)~ denote the square at the ~i~ -th row from the top and ~j~ -th column from the left. On each square, we can write a letter: R
, D
, or X
. Initially, every square is empty.
Snuke chose ~K~ of the squares and wrote characters on them. The ~i~ -th square he chose was ~(h_i,w_i)~ , and he wrote the letter ~c_i~ on it.
There are ~3^{HW-K}~ ways to write a letter on each of the remaining squares. Find the sum of the answers to the problem below for all those ~3^{HW-K}~ ways, modulo ~998244353~ .
We have a robot that can walk on the grid. When it is at ~(i,j)~ , it can move to ~(i+1, j)~ or ~(i, j+1)~ .
However, ifR
is written on ~(i, j)~ , it can only move to ~(i, j+1)~ ; ifD
is written on ~(i, j)~ , it can only move to ~(i+1, j)~ . IfX
is written on ~(i, j)~ , both choices are possible.When the robot is put at ~(1, 1)~ , how many paths can the robot take to reach ~(H, W)~ without going out of the grid? We assume the robot halts when reaching ~(H, W)~ .
Here, we distinguish two paths when the sets of squares traversed by the robot are different.
Constraints
- ~2 \leq H,W \leq 5000~
- ~0 \leq K \leq \min(HW,2 \times 10^5)~
- ~1 \leq h_i \leq H~
- ~1 \leq w_i \leq W~
- ~(h_i,w_i) \neq (h_j,w_j)~ for ~i \neq j~ .
- ~c_i~ is
R
,D
, orX
.
Input
Input is given from Standard Input in the following format:
~H~ ~W~ ~K~
~h_1~ ~w_1~ ~c_1~
~\vdots~
~h_K~ ~w_K~ ~c_K~
Output
Print the answer.
Sample Input 1
2 2 3
1 1 X
2 1 R
2 2 R
Sample Output 1
5
- Only ~(1,2)~ is empty.
- If we write
R
on it, there is one way that the robot can take to reach ~(H, W)~ . - If we write
D
on it, there are two ways that the robot can take to reach ~(H, W)~ . - If we write
X
on it, there are two ways that the robot can take to reach ~(H, W)~ .
- If we write
- We should print the sum of these counts: ~5~ .
Sample Input 2
3 3 5
2 3 D
1 3 D
2 1 D
1 2 X
3 1 R
Sample Output 2
150
Sample Input 3
5000 5000 10
585 1323 R
2633 3788 X
1222 4989 D
1456 4841 X
2115 3191 R
2120 4450 X
4325 2864 X
222 3205 D
2134 2388 X
2262 3565 R
Sample Output 3
139923295
- Be sure to compute the sum modulo ~998244353~ .
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