Dear Pythonistas (I hope you don't mind that), I wrote the following code to find the four adjacent numbers (in any direction in the array) which, when multiplied together, would yield the highest product to be gotten. I finally stumbled on the answer while studying the data itself but I'm still stumped as to why I keep getting an error while running the code. I would like answers to this and also any suggestions as to more elegant ways of solving this problem.
THE CODE data = [[ 8, 02, 22, 97, 38, 15, 00, 40, 00, 75, 04, 05, 07, 78, 52, 12, 50, 77, 91, 8], [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, 8, 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, 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, 03, 80, 04, 62, 16, 14, 9, 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, 8, 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, 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, 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]] def down_right_product(row, col): if (row>len(data)-3) or (col>len(data[row])-3): return 1 else: return reduce(lambda x,y:x*y, [data[row+each][col+each] for each in range(4)]) def down_left_product(row, col): if (row>len(data)-3) or (col<3): return 1 else: return reduce(lambda x,y:x*y, [data[row-each][col-each] for each in range(4)]) def right_product(row, col): if col>len(data[row])-3: return 0 else: return reduce(lambda x,y:x*y, [data[row][i] for i in range(col, col+4)]) def down_product(row, col): if row>len(data)-3: return 1 else: return reduce(lambda x,y:x*y, [data[i][col] for i in range(row, row+4)]) def main(): prod = 1 source = [] for row in range(len(data)): for col in range(len(data[row])): if right_product(row, col) > prod: prod = right_product(row, col) source = [data[row][i] for i in range(col, col+4)] if down_product(row, col) > prod: prod = down_product(row, col) source = [data[i][col] for i in range(row, row+4)] if down_right_product(row, col) > prod: prod = down_right_product(row, col) source = [data[row+each][col+each] for each in range(4)] if down_left_product(row, col) > prod: prod = down_left_product(row, col) source = [data[row-each][col-each] for each in range(4)] print 'Maximum product is %d from %l' %(prod, source) if __name__ == '__main__': main() THE ERROR Traceback (most recent call last): File "C:\Windows.old\Users\Abasiemeka\Abasiemeka\GOOGLE University\Python\Python Code\MyCode\Project Euler code\Project Euler answer 11.py", line 84, in <module> main() File "C:\Windows.old\Users\Abasiemeka\Abasiemeka\GOOGLE University\Python\Python Code\MyCode\Project Euler code\Project Euler answer 11.py", line 64, in main if right_product(row, col) > prod: File "C:\Windows.old\Users\Abasiemeka\Abasiemeka\GOOGLE University\Python\Python Code\MyCode\Project Euler code\Project Euler answer 11.py", line 49, in right_product return reduce(lambda x,y:x*y, [data[row][i] for i in range(col, col+4)]) IndexError: list index out of range p.s I apologise for the lack of comments Regards, Abasiemeka
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