A easy python solution.
The below code is a class Solution that defines a method largestPerimeter which takes in an input array A representing the lengths of the sides of a triangle.\n
The below code is a class Solution that defines a method largestPerimeter which takes in an input array A representing the lengths of the sides of a triangle.\n\nThe first line of the function sorts the input array in descending order using the sort() method with the reverse=True argument. This is done so that the largest side of the triangle will be at the first index of the array after sorting.\n\nThen the function uses a for loop to iterate through the sorted array starting from the first index to the second last index, which is represented by the range (len(A)-2).\n\nThe loop assigns the first element of the array to the variable a, the second element to the variable b, and the third element to the variable c at each iteration.\n\nThen it checks if the variable a is less than the sum of b and c using an if statement. If this condition is true, it means that the sides b and c are longer than the side a and therefore can form a triangle. In this case, the function returns the sum of the three sides a, b, and c as the largest perimeter.\n\nIf the if statement is not true, the loop continues iterating through the array until it finds a combination of sides that can form a triangle or until it reaches the end of the array.\n\nIf the loop ends and no combination of sides that can form a triangle is found, the function returns 0 as the answer.\n\n# Code\n```\nclass Solution(object):\n    def largestPerimeter(self, A):\n        A.sort(reverse=True)\n\n        for i in range(len(A)-2):\n            a = A[i]\n            b= A[i+1]\n            c = A[i+2]\n            if a< b+ c:\n                return a+b+c\n            \n        return 0\n```
['Python', 'Python3']