As mentioned in the title, I'm trying to find the greatest product of diagonal adjacent numbers in a grid but without using the numpy library.
dataa = [
[1,2,3,4,5],
[1,2,3,4,5],
[2,3,4,5,6],
[5,6,8,9,10],
[1,2,3,4,5]
]
def search_dr(data, length): # length = how many adjacent numbers to check
result, size = 0, len(data[0])
for i in range(size):
for y in range(0, len(data) - (length - 1)):
part, counter = [], 0
while len(part) < length:
if size >= i + (length - 1): # for downward diagonal
part.append(data[y + counter][i + counter])
counter += 1
product = 1
for x in part:
product *= x
if product > result:
result = product
if length - 1 <= i: # for upward diagonal
part.append(data[y + counter][i - counter])
counter += 1
product = 1
for x in part:
product *= x
if product > result:
result = product
return result
search_dr(dataa, 4)
expected output is 480 since it is the result of 5 * 4 * 4 * 6 which are adjacent numbers and their product would be the greatest product among other 4 adjacent number in the sample grid.
But I can't understand why it doesn't work and in most cases it gives an index error. I would appreciate it a lot if anyone could help me to understand my code problem.
main sample:
[8,2,22,97,38,15,00,40,00,75,4,5,7,78,52,12,50,77,91,8],
[49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,00],
[81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65],
[52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91],
[22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80],
[24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50],
[32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70],
[67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21],
[24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72],
[21,36,23,9,75,00,76,44,20,45,35,14,00,61,33,97,34,31,33,95],
[78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92],
[16,39,5,42,96,35,31,47,55,58,88,24,00,17,54,24,36,29,85,57],
[86,56,00,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58],
[19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40],
[4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66],
[88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69],
[4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36],
[20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16],
[20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54],
[1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48]
expected output: 70600674 [89, 94, 97, 87]
You should take a simpler approach and only process positions that are part of a 4 value diagonal. This can be obtained by identifying the subset of the matrix that contains the top left items and going down 4 positions from those.
For example:
data = [
[1,2,3,4,5],
[1,2,3,4,5],
[2,3,4,5,6],
[5,6,8,9,10],
[1,2,3,4,5]]
result = 0
values = []
diagLen = 4
for diagDir in (1,-1):
for r in range(len(data)-diagLen+1):
for c in range(len(data[0])-diagLen+1):
if diagDir<0 : c = len(data[0])-1-c
prod = 1
for i in range(diagLen): prod *= data[r+i][c+i*diagDir]
if prod<result: continue
result = prod
values = [data[r+i][c+i*diagDir] for i in range(diagLen)]
print(result,values)
# 480 [5, 4, 4, 6]