euler/python/e011.py

"""What is the greatest product of four numbers on the same straight line in the 20 by 20 grid?

In the 2020 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 any direction (up, down, left, right, or diagonally) in the 2020 grid?
"""

GRID = """
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
""".strip().replace('\n', ' ').split(' ')
GRID = [int(n) for n in GRID]

def product(l):
    p = 1
    for n in l:
        p = p * n
    return p

def main():
    max = 0
    info = None
    
    for row in range(1,20):
        for col in range(20):
            pos = 20 * row + col
            
            if col <= 16:
                # Horizontal
                r = GRID[pos:pos+4]
                x = product(r)
                if x > max:
                    max = x
                    info = [col, row, '-', r]
            if row <= 16:
                # Vertical
                r = []
                for i in range(4):
                    r.append(GRID[pos + 20 * i])
                x = product(r)
                if x > max:
                    max = x
                    info = [col, row, '|', r]
                
                if col <= 16:
                    # Diagonal (\)
                    r = []
                    for i in range(4):
                        r.append(GRID[pos + 20 * i + i])
                    x = product(r)
                    if x > max:
                        max = x
                        info = [col, row, '\\', r]
                if col >= 3:
                    # Diagonal (/)
                    r = []
                    for i in range(4):
                        r.append(GRID[pos + 20 * i - i])
                    x = product(r)
                    if x > max:
                        max = x
                        info = [col, row, '/', r]
    
    (col, row, direction, l) = info
    print 'Max Product is {p} at row {row}, col {col} ({d}): {l}'.format(p=max, row=row, col=col, d=direction, l=l)

if __name__ == '__main__':
    main()