Add code for leetcode 976.

Author: yanglr

Diff for: leetcode-976/leetcode976.py

@@ -0,0 +1,15 @@
+from typing import List
+class Solution:
+    def largestPerimeter(self, A: List[int]) -> int:
+        if (len(A) < 3):
+            return 0
+
+        A.sort(reverse=True)
+        for i in range(len(A)-2):
+            if A[i] < A[i+1] + A[i+2]:  # Can build a triangle
+                return A[i] + A[i+1] + A[i+2]
+        return 0
+
+# Below is testing
+sol = Solution()
+print(sol.largestPerimeter([4, 5, 2, 7]))