Syntax error Program to find length of longest contiguously strictly increasing sublist after removal in Python

Program to find length of longest contiguously strictly increasing sublist after removal in Python

Suppose we have a list of numbers called nums, we have to find the maximum length of a contiguous strictly increasing sublist. We are allowed to remove at most single element from the list.

So, if the input is like nums = [35, 5, 6, 7, 8, 9, 12, 11, 26], then the output will be 7, because if we remove 12 from nums, the list will be [5, 6, 7, 8, 9, 11, 26], the length is 7, this is the longest, contiguous, strictly increasing sub-list.

To solve this, we will follow these steps −

  • if nums is empty, then
    • return 0
  • end := a list of size same as nums and fill with 1
  • start := a list of size same as nums and fill with 1
  • for i in range 1 to size of nums - 1, do
    • if nums[i] > nums[i - 1], then
      • end[i] := end[i - 1] + 1
  • for j in range size of nums - 2 to 0, decrease by 1, do
    • if nums[j + 1] > nums[j], then
      • start[j] := start[j + 1] + 1
  • res := maximum of the elements of end and element of start
  • for k in range 1 to size of nums - 2, do
    • if nums[k - 1] < nums[k + 1], then
      • res := maximum of res and (end[k - 1] + start[k + 1])
  • return res

Example

Let us see the following implementation to get better understanding −

def solve(nums):
   if not nums:
      return 0
   end = [1 for i in nums]
   start = [1 for i in nums]

   for i in range(1, len(nums)):
      if nums[i] > nums[i - 1]:
         end[i] = end[i - 1] + 1

   for j in range(len(nums) - 2, -1, -1):
      if nums[j + 1] > nums[j]:
         start[j] = start[j + 1] + 1

   res = max(max(end), max(start))

   for k in range(1, len(nums) - 1):
      if nums[k - 1] < nums[k + 1]:
         res = max(res, end[k - 1] + start[k + 1])

   return res

nums = [35, 5, 6, 7, 8, 9, 12, 11, 26]
print(solve(nums))

Input

[35, 5, 6, 7, 8, 9, 12, 11, 26]

Output

7
Updated on: 2021-10-19T10:37:33+05:30

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