ClickHouse 数组 - 在数组中找到最长的重复数字链

Question

在 Clickhouse 中，我有一列包含 Int16 元素的数组。我正在寻找一种方法来找到最长的重复数字 1 链。例如，数组 [0,1,1,1,5,1,1,1,1,1,2] 中重复 1 的最长链为 5 个元素。有什么办法可以用现有的函数来做吗？

Answer 1

试试这个查询：

SELECT
    /* The source number. */
    data.1 AS number,
    /* The source array. */
    data.2 AS array,
    /* Number the values in each chain. */
    arrayCumSumNonNegative((x, index) -> x = number ? 1 : -index, array, arrayEnumerate(array)) AS partiallySumArray,
    arrayReduce('max', partiallySumArray) AS result
FROM
(
    /* test data set */
    SELECT arrayJoin([
      /**/
      (1, []), 
      (1, [0, 2, 2, 2, 5]), 
      (1, [0, 1, 1, 1, 5, 1, 1, 1, 1, 1,2]), 
      (1, [1, 1, 1, 2, 3, 4, 5, 1, 1]), 
      (1, [-5, 100, 1, 1, 0, 1, 1, 1]),
      (1, [1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0]),
      /**/
      (5, []), 
      (5, [0, 2, 2, 2, 55]),       
      (5, [5, 5, 10, 300, 5, 77, 5])
      ]) AS data
)
FORMAT Vertical

/* Result:

Row 1:
──────
number:            1
array:             []
partiallySumArray: []
result:            0

Row 2:
──────
number:            1
array:             [0,2,2,2,5]
partiallySumArray: [0,0,0,0,0]
result:            0

Row 3:
──────
number:            1
array:             [0,1,1,1,5,1,1,1,1,1,2]
partiallySumArray: [0,1,2,3,0,1,2,3,4,5,0]
result:            5

Row 4:
──────
number:            1
array:             [1,1,1,2,3,4,5,1,1]
partiallySumArray: [1,2,3,0,0,0,0,1,2]
result:            3

Row 5:
──────
number:            1
array:             [-5,100,1,1,0,1,1,1]
partiallySumArray: [0,0,1,2,0,1,2,3]
result:            3

Row 6:
──────
number:            1
array:             [1,1,0,1,1,1,1,1,1,0,0]
partiallySumArray: [1,2,0,1,2,3,4,5,6,0,0]
result:            6

Row 7:
──────
number:            5
array:             []
partiallySumArray: []
result:            0

Row 8:
──────
number:            5
array:             [0,2,2,2,55]
partiallySumArray: [0,0,0,0,0]
result:            0

Row 9:
───────
number:            5
array:             [5,5,10,300,5,77,5]
partiallySumArray: [1,2,0,0,1,0,1]
result:            2
*/

ClickHouse 数组 - 在数组中找到最长的重复数字链

ClickHouse array - find a longest chain of repeating number in array

arrays

function

clickhouse