Post date: May 26, 2014 2:57:35 PM
"Find the greatest product of four adjacent numbers, in any direction, in a certain grid of numbers?"
Remember to check all directions, including diagonal left/down. It's easy to forget.
DECLARE @BigString varchar(4000)
SET @BigString =
'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 '
CREATE TABLE #Working (
num INT NOT NULL,
row INT NOT NULL,
col INT NOT NULL,
PRIMARY KEY (row, col)
)
DECLARE @row int = 0, @col int = 0
SET @BigString = REPLACE(@BigString,' ','')
-- Load the grid into a table
WHILE 1 = 1
BEGIN
INSERT INTO #Working (num, row, col)
SELECT LEFT(@BigString,2), @row, @col
SET @BigString = STUFF(@BigString,1,2,'')
IF @BigString = '' BREAK
IF @col = 19
SELECT @col = 0, @row = @row + 1
ELSE
SET @col = @col + 1
END -- While
; WITH ConnectFour (a, b, c, d) AS
(
-- Horizontal
SELECT t1.num, t2.num, t3.num, t4.num
FROM #Working t1
INNER JOIN #Working t2
ON t2.row = t1.row
AND t2.col = t1.col + 1
INNER JOIN #Working t3
ON t3.row = t2.row
AND t3.col = t2.col + 1
INNER JOIN #Working t4
ON t4.row = t3.row
AND t4.col = t3.col + 1
UNION ALL
-- Vertical
SELECT t1.num, t2.num, t3.num, t4.num
FROM #Working t1
INNER JOIN #Working t2
ON t2.row = t1.row + 1
AND t2.col = t1.col
INNER JOIN #Working t3
ON t3.row = t2.row + 1
AND t3.col = t2.col
INNER JOIN #Working t4
ON t4.row = t3.row + 1
AND t4.col = t3.col
UNION ALL
-- Diagonal right
SELECT t1.num, t2.num, t3.num, t4.num
FROM #Working t1
INNER JOIN #Working t2
ON t2.row = t1.row + 1
AND t2.col = t1.col + 1
INNER JOIN #Working t3
ON t3.row = t2.row + 1
AND t3.col = t2.col + 1
INNER JOIN #Working t4
ON t4.row = t3.row + 1
AND t4.col = t3.col + 1
UNION ALL
-- Diagonal left
SELECT t1.num, t2.num, t3.num, t4.num
FROM #Working t1
INNER JOIN #Working t2
ON t2.row = t1.row + 1
AND t2.col = t1.col - 1
INNER JOIN #Working t3
ON t3.row = t2.row + 1
AND t3.col = t2.col - 1
INNER JOIN #Working t4
ON t4.row = t3.row + 1
AND t4.col = t3.col - 1
)
SELECT MAX(a * b * c * d)
FROM ConnectFour
DROP TABLE #Working