# Simple Sudoku solver in python

Hi there pythonistas! We all know that Sudoku is a great game. Some of us even bet on this game but did you know that you can use python to make a Sudoku solver? In this post I am going to share with you a Sudoku solver written in python.

From now on you will win all Sudoku challenges. However let me tell you that I am not the original writer of this script. I stumbled over this script on stack-overflow. So without wasting any time let me share the script with you:

```
import sys
def same_row(i,j): return (i/9 == j/9)
def same_col(i,j): return (i-j) % 9 == 0
def same_block(i,j): return (i/27 == j/27 and i%9/3 == j%9/3)
def r(a):
i = a.find('0')
if i == -1:
sys.exit(a)
excluded_numbers = set()
for j in range(81):
if same_row(i,j) or same_col(i,j) or same_block(i,j):
excluded_numbers.add(a[j])
for m in '123456789':
if m not in excluded_numbers:
r(a[:i]+m+a[i+1:])
if __name__ == '__main__':
if len(sys.argv) == 2 and len(sys.argv[1]) == 81:
r(sys.argv[1])
else:
print 'Usage: python sudoku.py puzzle'
print ' where puzzle is an 81 character string
representing the puzzle read left-to-right,
top-to-bottom, and 0 is a blank'
```

Hey there wait! let me share with you a shorter obfuscated version of the same Sudoku solving script. However this short version of Sudoku solver is a lot slower but I think that I should share it with you just to show you that even in python obfuscated code can be written. So here is the shorter obfuscated version:

```
def r(a):i=a.find('0');~i or exit(a);[m
in[(i-j)%9*(i/9^j/9)*(i/27^j/27|i%9/3^j%9/3)or a[j]for
j in range(81)]or r(a[:i]+m+a[i+1:])for m in'%d'%5**18]
from sys import*;r(argv[1])
```

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Daniel

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