added a buddy strings implementation

Author: barrotsteindev

LeetCode/0859_Buddy_String.py

@@ -0,0 +1,13 @@
+class Solution:
+    def buddyStrings(self, A: str, B: str) -> bool:
+        indexes_to_swap = []
+        for idx, string in enumerate(A):
+            if string != B[idx]:
+                indexes_to_swap.append(idx)
+                if len(indexes_to_swap) > 2:
+                    return False
+        
+        if len(indexes_to_swap) != 2:
+            return false
+        
+        return A[indexes_to_swap[0]] == B[indexes_to_swap[1]] and A[indexes_to_swap[1]] == B[indexes_to_swap[0]]