2026 年 USACO竞赛 首场比赛白金组问题三—Pluses and Minuses

Farmer John once painted a rectangular grid on the ground of his pasture. In each cell, he painted either a + or a −(representing +1 and −1, respectively).

Over time, the paint faded, and Farmer John now remembers the values of only some cells. However, Farmer John does remember one important fact about the original painting:

In every row and every column, the sum of the values in any contiguous subsegment was always between −1 and 2 (inclusive).

As an example, consider the row + - - +. It does not satisfy the condition, since the subsegment + [ - - ] + has sum −2.

However, the row - + + -does satisfy the condition.

[ - ] + + -          sum = -1
[ - + ] + -          sum = 0
[ - + + ] -          sum = +1
[ - + + - ]          sum = 0
- [ + ] + -          sum = +1
- [ + + ] -          sum = +2
- [ + + - ]          sum = +1
- + [ + ] -          sum = +1
- + [ + - ]          sum = 0
- + + [ - ]          sum = -1

Count the number of different grids consistent with Farmer John's memory.

INPUT FORMAT (input arrives from the terminal / stdin):

The first line contains T(1≤T≤100), the number of independent tests. Each test is specified as follows:

The first line contains R, C, and X (1≤R,C≤5⋅105, 0≤X≤min(105,RC)), meaning that the grid has dimensions R×C and Farmer John remembers the values of X
different cells in the grid.

Then following X lines each contain a character v∈{+,−} followed by two integers r and c (1≤ r R, 1≤ cC), meaning that the value at the rth row and cth column of the grid is v. It is guaranteed that no ordered pair (r,c) appears more than once within a single test.

Additionally, it is guaranteed that neither the sum of R nor the sum of C over all tests exceeds 106, and that the sum of X over all tests does not exceed 2⋅105.

OUTPUT FORMAT (print output to the terminal / stdout):

For each test, output the number of grids on a separate line.

SAMPLE INPUT:

2
1 3 3
+ 1 3
+ 1 1
- 1 2
1 3 3
+ 1 1
+ 1 3
+ 1 2

SAMPLE OUTPUT:

1
0

SAMPLE INPUT:

1
2 2 0

SAMPLE OUTPUT:

7

Here are the seven grids:

++
++

++
+-

++
-+

+-
++

+-
-+

-+
++

-+
+-

SCORING:

Inputs 3-4: min(R,C)=1for all tests
Inputs 5-6: R,C≤10 for all tests
Inputs 7-11: ∑max(R,C)2≤106
Inputs 12-14: ∑RC≤106
Inputs 15-22: No additional constraints.

Problem credits: Alex Chen