human
Solve in Python:
Given an array A of positive lengths, return the largest perimeter of a triangle with non-zero area, formed from 3 of these lengths.
If it is impossible to form any triangle of non-zero area, return 0.
 


Example 1:
Input: [2,1,2]
Output: 5

Example 2:
Input: [1,2,1]
Output: 0

Example 3:
Input: [3,2,3,4]
Output: 10

Example 4:
Input: [3,6,2,3]
Output: 8

 
Note:

3 <= A.length <= 10000
1 <= A[i] <= 10^6
 Give me a the Python program you requested?
assistant
#Here is the Python program you requested.

class Solution:
    def largestPerimeter(self, A: List[int]) -> int:
      res = 0
      A.sort()
      for i in range(len(A)):
        for j in range(i+1, len(A)):
          source = A[i]
          target = A[j]
          lower = abs(target - source)
          upper = source + target
          if (upper*2 < res):
            continue
          for t in range(j+1, len(A)):
            if lower < A[t] < upper:
              res = max(source + target + A[t], res)
              break
          if res != 0:
            break
      return res