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Add minmum path sum (TheAlgorithms#5882)
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* commit on 'shortest_path_sum'

* minimum_path_sum updated

* commit to 'minimum_path_sum'

* added description to minimum_path_sum

* bot requirements fixed for

* Update minimum_path_sum.py

* Update minimum_path_sum.py

Co-authored-by: John Law <[email protected]>
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rainelegary and poyea authored May 25, 2022
1 parent de4d980 commit b8fdd81
Showing 1 changed file with 63 additions and 0 deletions.
63 changes: 63 additions & 0 deletions graphs/minimum_path_sum.py
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def min_path_sum(grid: list) -> int:
"""
Find the path from top left to bottom right of array of numbers
with the lowest possible sum and return the sum along this path.
>>> min_path_sum([
... [1, 3, 1],
... [1, 5, 1],
... [4, 2, 1],
... ])
7
>>> min_path_sum([
... [1, 0, 5, 6, 7],
... [8, 9, 0, 4, 2],
... [4, 4, 4, 5, 1],
... [9, 6, 3, 1, 0],
... [8, 4, 3, 2, 7],
... ])
20
>>> min_path_sum(None)
Traceback (most recent call last):
...
TypeError: The grid does not contain the appropriate information
>>> min_path_sum([[]])
Traceback (most recent call last):
...
TypeError: The grid does not contain the appropriate information
"""

if not grid or not grid[0]:
raise TypeError("The grid does not contain the appropriate information")

for cell_n in range(1, len(grid[0])):
grid[0][cell_n] += grid[0][cell_n - 1]
row_above = grid[0]

for row_n in range(1, len(grid)):
current_row = grid[row_n]
grid[row_n] = fill_row(current_row, row_above)
row_above = grid[row_n]

return grid[-1][-1]


def fill_row(current_row: list, row_above: list) -> list:
"""
>>> fill_row([2, 2, 2], [1, 2, 3])
[3, 4, 5]
"""

current_row[0] += row_above[0]
for cell_n in range(1, len(current_row)):
current_row[cell_n] += min(current_row[cell_n - 1], row_above[cell_n])

return current_row


if __name__ == "__main__":
import doctest

doctest.testmod()

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