111 lines
4.2 KiB
Ruby
111 lines
4.2 KiB
Ruby
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# In the 20×20 grid below, four numbers along a diagonal line have been marked in red.
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#
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# 08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
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# 49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
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# 81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
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# 52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
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# 22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
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# 24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
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# 32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
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# 67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
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# 24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
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# 21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
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# 78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
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# 16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
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# 86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
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# 19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
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# 04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
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# 88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
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# 04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
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# 20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
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# 20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
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# 01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48
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#
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# The product of these numbers is 26 × 63 × 78 × 14 = 1788696.
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#
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# What is the greatest product of four adjacent numbers in any direction (up, down, left, right, or diagonally) in the 20×20 grid?
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data=%{08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08
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49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00
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81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65
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52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91
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22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80
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24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50
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32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70
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67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21
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24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72
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21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95
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78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92
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16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57
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86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58
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19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40
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04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66
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88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69
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04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36
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20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16
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20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54
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01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48}
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matrix=data.split("\n").collect! { |line| line.split(" ").collect! { |x| x.to_i }}
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size=4
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max=0
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# Horizontal
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(0..matrix.length-1).each do |ligne|
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(0..(matrix[ligne].length - size)).each do |col|
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prod=1
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(0..size-1).each do |i|
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prod = prod * matrix[ligne][col+i]
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# print matrix[ligne][col+i].to_s + " "
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if prod>max
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max=prod
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end
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end
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# print "\n"
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end
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end
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# Vertical
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(0..matrix.length-size).each do |ligne|
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(0..(matrix[ligne].length - 1)).each do |col|
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prod=1
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(0..size-1).each do |i|
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prod = prod * matrix[ligne+i][col]
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# print matrix[ligne][col+i].to_s + " "
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if prod>max
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max=prod
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end
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end
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end
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end
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# Diagonal positive
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(0..matrix.length-size).each do |ligne|
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(0..(matrix[ligne].length - size)).each do |col|
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prod=1
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(0..size-1).each do |i|
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prod = prod * matrix[ligne+i][col+i]
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# print matrix[ligne][col+i].to_s + " "
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if prod>max
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max=prod
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end
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end
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end
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end
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# Diagonal negative
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(0..matrix.length-size).each do |ligne|
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(size..(matrix[ligne].length - 1)).each do |col|
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prod=1
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(0..size-1).each do |i|
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prod = prod * matrix[ligne+i][col-i]
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# print matrix[ligne][col+i].to_s + " "
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if prod>max
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max=prod
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end
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end
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end
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end
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puts max
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