mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-06 13:49:30 +00:00
94 lines
3.0 KiB
Python
94 lines
3.0 KiB
Python
"""
|
|
What is the greatest product of four adjacent numbers (horizontally,
|
|
vertically, or diagonally) in this 20x20 array?
|
|
|
|
08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
|
|
49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
|
|
81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
|
|
52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
|
|
22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
|
|
24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
|
|
32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
|
|
67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
|
|
24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
|
|
21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
|
|
78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
|
|
16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
|
|
86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
|
|
19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
|
|
04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
|
|
88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
|
|
04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
|
|
20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
|
|
20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
|
|
01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48
|
|
"""
|
|
|
|
import os
|
|
|
|
|
|
def largest_product(grid):
|
|
nColumns = len(grid[0])
|
|
nRows = len(grid)
|
|
|
|
largest = 0
|
|
lrDiagProduct = 0
|
|
rlDiagProduct = 0
|
|
|
|
# Check vertically, horizontally, diagonally at the same time (only works
|
|
# for nxn grid)
|
|
for i in range(nColumns):
|
|
for j in range(nRows - 3):
|
|
vertProduct = (
|
|
grid[j][i] * grid[j + 1][i] * grid[j + 2][i] * grid[j + 3][i]
|
|
)
|
|
horzProduct = (
|
|
grid[i][j] * grid[i][j + 1] * grid[i][j + 2] * grid[i][j + 3]
|
|
)
|
|
|
|
# Left-to-right diagonal (\) product
|
|
if i < nColumns - 3:
|
|
lrDiagProduct = (
|
|
grid[i][j]
|
|
* grid[i + 1][j + 1]
|
|
* grid[i + 2][j + 2]
|
|
* grid[i + 3][j + 3]
|
|
)
|
|
|
|
# Right-to-left diagonal(/) product
|
|
if i > 2:
|
|
rlDiagProduct = (
|
|
grid[i][j]
|
|
* grid[i - 1][j + 1]
|
|
* grid[i - 2][j + 2]
|
|
* grid[i - 3][j + 3]
|
|
)
|
|
|
|
maxProduct = max(
|
|
vertProduct, horzProduct, lrDiagProduct, rlDiagProduct
|
|
)
|
|
if maxProduct > largest:
|
|
largest = maxProduct
|
|
|
|
return largest
|
|
|
|
|
|
def solution():
|
|
"""Returns the sum of all the multiples of 3 or 5 below n.
|
|
|
|
>>> solution()
|
|
70600674
|
|
"""
|
|
grid = []
|
|
with open(os.path.dirname(__file__) + "/grid.txt") as file:
|
|
for line in file:
|
|
grid.append(line.strip("\n").split(" "))
|
|
|
|
grid = [[int(i) for i in grid[j]] for j in range(len(grid))]
|
|
|
|
return largest_product(grid)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
print(solution())
|