|| ||Code Submission Evaluation System
CSES Problem Set
Task | Statistics
CSES - Grid PathsCSES - Grid Paths
|Time limit:||1.00 s
||Memory limit:||512 MB|
Consider an $n \times n$ grid whose squares may have traps. It is not allowed to move to a square with a trap.
Your task is to calculate the number of paths from the upper-left square to the lower-right square where you only can move right or down.
The first input line has an integer $n$: the size of the grid.
After this, there are $n$ lines that describe the grid. Each line has $n$ characters:
denotes an empty cell, and
denotes a trap.
Print the number of paths modulo $10^9+7$.