Largest product in a grid
这个比前面的要复杂点，但找对了规律，还是可以的。
我逻辑思维不强，只好画图来数数列的下标了。
分四次计算，存入最大值。
左右一次，上下一次，左斜一次，右斜一次。
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 2020 grid?
str = "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 " numList = str.split() print numList print len(numList) maxNum = 0 for i in xrange(0,len(numList)-3): if (i % 20 == 18) or (i % 20 == 19) or (i % 20 == 17) : continue curNum = int(numList[i])*int(numList[i+1])*int(numList[i+2])*int(numList[i+3]) if curNum > maxNum: maxNum = curNum #print i,curNum,maxNum for i in xrange(0,len(numList)): if (i >= 340): break curNum = int(numList[i])*int(numList[i+20])*int(numList[i+40])*int(numList[i+60]) if curNum > maxNum: maxNum = curNum #print i,curNum,maxNum for i in xrange(0,len(numList)): if (i >= 340): break if (i % 20 == 18) or (i % 20 == 19) or (i % 20 == 17) : continue curNum = int(numList[i])*int(numList[i+21])*int(numList[i+42])*int(numList[i+63]) if curNum > maxNum: maxNum = curNum #print i,curNum,maxNum for i in xrange(0,len(numList)): if (i < 60): continue if (i % 20 == 18) or (i % 20 == 19) or (i % 20 == 17) : continue curNum = int(numList[i])*int(numList[i-19])*int(numList[i-38])*int(numList[i-57]) if curNum > maxNum: maxNum = curNum #print numList[i],numList[i-19],numList[i-38],numList[i-57],curNum,maxNum print maxNum
