algorithm/Python
1
0
Fork 0
mirror of https://github.com/TheAlgorithms/Python.git synced 2025-07-19 19:03:02 +08:00
Code Issues Packages Projects Releases Wiki Activity

Added doctest and more explanation about Dijkstra execution. (#1014)

Browse Source 
* Added doctest and more explanation about Dijkstra execution.

* tests were not passing with python2 due to missing __init__.py file at number_theory folder

* Removed the dot at the beginning of the imported modules names because 'python3 -m doctest -v data_structures/hashing/*.py' and 'python3 -m doctest -v data_structures/stacks/*.py' were failing not finding hash_table.py and stack.py modules.

* Moved global code to main scope and added doctest for project euler problems 1 to 14.

* Added test case for negative input.

* Changed N variable to do not use end of line scape because in case there is a space after it the script will break making it much more error prone.

* Added problems description and doctests to the ones that were missing. Limited line length to 79 and executed python black over all scripts.

* Changed the way files are loaded to support pytest call.

* Added __init__.py to problems to make them modules and allow pytest execution.

* Added project_euler folder to test units execution

* Changed 'os.path.split(os.path.realpath(__file__))' to 'os.path.dirname()'
This commit is contained in:
Bruno Simas Hadlich
2019-07-16 20:09:53 -03:00
committed by cclauss
parent 2fb3beeaf1
commit 267b5eff40
100 changed files with 2621 additions and 1438 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
project_euler/problem_15/sol1.py
View File

@ -1,20 +1,57 @@
from __future__ import print_function
"""
Starting in the top left corner of a 2×2 grid, and only being able to move to
the right and down, there are exactly 6 routes to the bottom right corner.
How many such routes are there through a 20×20 grid?
"""
from math import factorial
def lattice_paths(n):
n = 2*n #middle entry of odd rows starting at row 3 is the solution for n = 1, 2, 3,...
k = n/2
"""
Returns the number of paths possible in a n x n grid starting at top left
corner going to bottom right corner and being able to move right and down
only.
return factorial(n)/(factorial(k)*factorial(n-k))
bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 50
1.008913445455642e+29
bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 25
126410606437752.0
bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 23
8233430727600.0
bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 15
155117520.0
bruno@bruno-laptop:~/git/Python/project_euler/problem_15$ python3 sol1.py 1
2.0
if __name__ == '__main__':
import sys
>>> lattice_paths(25)
126410606437752
>>> lattice_paths(23)
8233430727600
>>> lattice_paths(20)
137846528820
>>> lattice_paths(15)
155117520
>>> lattice_paths(1)
2
if len(sys.argv) == 1:
print(lattice_paths(20))
else:
try:
n = int(sys.argv[1])
print(lattice_paths(n))
except ValueError:
print('Invalid entry - please enter a number.')
"""
n = (
2 * n
) # middle entry of odd rows starting at row 3 is the solution for n = 1,
# 2, 3,...
k = n / 2
return int(factorial(n) / (factorial(k) * factorial(n - k)))
if __name__ == "__main__":
import sys
if len(sys.argv) == 1:
print(lattice_paths(20))
else:
try:
n = int(sys.argv[1])
print(lattice_paths(n))
except ValueError:
print("Invalid entry - please enter a number.")