Program to find largest perimeter triangle using Python

Suppose we have an array nums of positive lengths, we have to find the largest perimeter of a triangle, by taking three values from that array. When it is impossible to form any triangle of non-zero area, then return 0.

So, if the input is like [8,3,6,4,2,5], then the output will be 19.

To solve this, we will follow these steps −

• sort the list nums

• a := delete last element from nums

• b := delete last element from nums

• c := delete last element from nums

• while b+c <= a, do

  • if not nums is non-zero, then

    • return 0

  • a := b

  • b := c

  • c := delete last element from nums

• return a+b+c

Let us see the following implementation to get better understanding −

Example

 Live Demo

def solve(nums):
   nums.sort()
   a, b, c = nums.pop(), nums.pop(), nums.pop()
   while b+c<=a:
      if not nums:
         return 0
      a, b, c = b, c, nums.pop()
   return a+b+c
nums = [8,3,6,4,2,5]
print(solve(nums))

Input

[8,3,6,4,2,5]

Output

19