Baltic Olympiad in Informatics: 2010 Day 2, Problem 3
Heino drew an grid. Each cell was either empty or contained a mine. Indrek, a good
friend of Heino, drew another
grid. In each cell of his grid, he wrote the total number of
mines in the corresponding cell of Heino's grid and all its adjacent cells (two cells are adjacent
if they share a common point). Indrek then erased Heino's grid. Given Indrek's grid, your task
is to help Heino restore his original grid.
You may assume that at least one solution always exists.
Constraints
or
Input Specification
The first line of the input file contains two integers: , the height of
the grid, and
, the width of the grid. The following
lines each contain
digits that describe Indrek's grid.
Output Specification
Output lines. Each of these lines should contain
characters:
X
for a mine and .
for an empty cell.
If there are several correct solutions, output any one of them.
Sample Input
3 5
24531
46631
34310
Sample Output
.XXX.
.XX..
XX...
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