Program to check whether given list of blocks are symmetric over x = y line or not in python

Suppose we have a list of numbers called nums. And it is representing the height of square blocks, we have to check whether the shape is symmetric over the y = x line or not.

So, if the input is like nums = [7, 5, 3, 2, 2, 1, 1], then the output will be True

To solve this, we will follow these steps:

• i := 0
• j := size of nums - 1
• while i <= j, do
  • h := nums[j]
  • while i < h, do
    • if nums[i] is not same as (j + 1), then
      • return False
    • i := i + 1
  • j := j - 1
• return True

Let us see the following implementation to get better understanding:

Example

Live Demo

class Solution:
   def solve(self, nums):
      i = 0
      j = len(nums) - 1
      while i <= j:
         h = nums[j]
         while i < h:
            if nums[i] != j + 1:
               return False
            i += 1
            j -= 1
      return True

ob = Solution()
nums = [7, 5, 3, 2, 2, 1, 1]
print(ob.solve(nums))

Input

[7, 5, 3, 2, 2, 1, 1]

Output

True

Arnab Chakraborty

Updated on: 26-Nov-2020

258 Views

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