Solutions

linked_lists/intersection.py

@@ -1,14 +1,44 @@
-
-
-
 class Node:
     def __init__(self, value):
         self.val = value
         self.next = None
 
 
+# BRUTE FORCE SOLUTION
+# def intersection_node(headA, headB):
+#     """ Will return the node at which the two lists intersect.
+#         If the two linked lists have no intersection at all, return None.
+#     """
+#     currentA = headA
+
+#     while currentA:
+#         currentB = headB
+
+#         while currentB:
+#             if currentA == currentB:
+#                 return currentA
+#             currentB = currentB.next
+
+#         currentA = currentA.next
+
+#     return None
+
+# SECOND SOLUTION
 def intersection_node(headA, headB):
-    """ Will return the node at which the two lists intersect.
-        If the two linked lists have no intersection at all, return None.
-    """
-    pass
+    d = {}
+
+    currentA = headA
+
+    while currentA:
+        d[currentA] = 0
+        currentA = currentA.next
+
+    currentB = headB
+
+    while currentB:
+        if currentB in d:
+            return currentB
+
+        currentB = currentB.next
+
+    return None