我正在刷掉我很久没有使用过的 MATLAB 技能。为此，我一直在 Project Eueler 上解决难题。好吧，我有点难倒这个，因为当我分成几部分时，一切似乎都运行良好，但我最大的数字显然不正确。
无论如何，这是我的代码 %这个脚本将采用一个网格并找到 4 个数字的最大乘积 %上、下、左、右和对角线
%create the 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;];
%grid(row, column)
%find how many rows and columns there are
[rowNum, columnNum] = size(grid);
%Current greatest product of four consecutive
greatest = 0;
%test left right
%iterate through all rows
for i = 1:rowNum
%iterate through all columns except the last tthree
for x = 1:columnNum-3
%test the consecutive numbers starting with the current colum
%iteration
current = 1;
for test = x:x+3
current = current * grid(i, test);
if greatest < current
greatest = current;
end
end
end
end
%iterate through all columns
for i = 1:columnNum
%iterate throw all rows except the last three
for x = 1:rowNum-3
%test the consecutive numbers starting with the current colum
%iteration
current = 1;
for test = x:x+3
current = current * grid(test, i);
if greatest < current
greatest = current;
end
end
end
end
for i = 1:columnNum-3
%iterate throw all column except the last two
for x = 1:rowNum-3
%test the consecutive numbers starting with the current colum
%iteration
current = 1;
%count adds the number of iterations to the row number in grid
%forcing it to move in a diagonal line
count = 0;
%test consecutively from x to three to the right
for test = x:x+3
%make new current product
current = current * grid(i+count, test);
%add to count to shift down one row next iteration
count = count + 1;
%check for greatest
if greatest < current
greatest = current;
end
end
end
end
disp(greatest)
我认为问题在于搜索对角线的嵌套 for 循环，但我不确定。我已经将它分解成多个部分（单独测试每个 for 循环，并在搜索它们时输出每个元素）。我很确定水平和垂直搜索方法可以正常工作。
只是想要一双新的眼睛来看看这个，谢谢！
此外，我确信有一种更有效的方法可以做到这一点，所以如果有人对更好的算法有一些想法，我很想听听！