DMOPC '22 Contest 4 P2 - Fake Painting
View as PDFIn the th century, Picasso used an unconventional painting technique to create his art. Initially, he started with a canvas 
 that can be represented by an 
 by 
 grid of integers. Let 
 denote the position of the cell in the 
-th row from the top and 
-th column from the left.
Picasso painted the canvas using a special type of brushstroke, which he used an unknown (possibly zero) number of times. Each brushstroke consisted of the following: First, he chose a nonzero integer  and a position 
. Then, he added 
 to cell 
, flipped the grid either horizontally or vertically, and added 
 to cell 
 again.
Specifically, a horizontal flip reverses the order of the columns, while a vertical flip reverses the order of the rows.
You want to buy one of Picasso's masterpieces, however, it could be a fake. Given the original canvas  and a potential canvas 
, determine if 
 could have been created by Picasso.
Constraints
Subtask 1 [30%]
Subtask 2 [70%]
No additional constraints.
Input Specification
The first line contains  space-separated integers 
 and 
.
The next  lines contain 
 space-separated integers 
 representing the cells of the original canvas.
The last  lines contain 
 space-separated integers 
 representing the cells of the potential canvas.
Output Specification
Output YES if  could have been created by Picasso, and 
NO otherwise.
Sample Input 1
2 2
1 2
3 5
2 1
4 2
Sample Output 1
YES
Explanation for Sample 1
Picasso can perform  brushstroke to transform 
 into 
: choose 
 as 
, add 
 to 
, flip the grid horizontally, and add 
 to 
 again.
Sample Input 2
2 2
1 2
3 5
1 2
3 6
Sample Output 2
NO
Explanation for Sample 2
No sequence of moves can be performed which transforms  to 
.
Sample Input 3
1 3
2 3 2
1 2 2
Sample Output 3
NO
Explanation for Sample 3
No sequence of moves can be performed which transforms  to 
.
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