[#11] Largest product in a grid

In the 20×20 grid below, four numbers along a diagonal line have been marked in red.

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

The product of these numbers is 26 × 63 × 78 × 14 = 1788696.
What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?

def problem11(n):
        '''
        In the 20×20 grid below, four numbers along a diagonal line have been marked in red.

        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

        The product of these numbers is 26 × 63 × 78 × 14 = 1788696.

        What is the greatest product of n adjacent numbers in the same direction
        (up, down, left, right, or diagonally) in the 20×20 grid?
        '''
        b1 = [8,2,22,97,38,15,00,40,00,75,4,5,7,78,52,12,50,77,91,8]
        b2 = [49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0]
        b3 = [81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65]
        b4 = [52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91]
        b5 = [22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80]
        b6 = [24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50]
        b7 = [32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70]
        b8 = [67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21]
        b9 = [24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72]
        b10 = [21,36,23,9,75,00,76,44,20,45,35,14,0,61,33,97,34,31,33,95]
        b11 = [78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92]
        b12 = [16,39,5,42,96,35,31,47,55,58,88,24,00,17,54,24,36,29,85,57]
        b13 = [86,56,00,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58]
        b14 = [19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40]
        b15 = [4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66]
        b16 = [88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69]
        b17 = [4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36]
        b18 = [20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16]
        b19 = [20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54]
        b20 = [1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48]
        board = [b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17,b18,b19,b20]
        result = 0
        for i in range(len(board)):
            for j in range(len(board)):
                if j <= len(board) - n:
                    temp = 1
                    for x in range(n):#left to right
                        temp *= board[i][j + x]
                    if temp > result:
                        result = temp

                    temp = 1
                    for x in range(n):#up to down
                        temp *= board[j + x][i]
                    if temp > result:
                        result = temp

                if i <= len(board) - n and j <= len(board) - n:
                    temp = 1
                    for x in range(n):#up-left to down-right
                        temp *= board[i + x][j + x]
                    if temp > result:
                        result = temp
                        
                if i >= n - 1 and j <= len(board) - n:
                    temp = 1
                    for x in range(n):#up-right to down-left
                        temp *= board[j + x][i - x]
                    if temp > result:
                        result = temp
        return result