[hu6r1s] WEEK 12 Solutions

remove-nth-node-from-end-of-list/hu6r1s.py

@@ -0,0 +1,20 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def removeNthFromEnd(self, head: Optional[ListNode], n: int) -> Optional[ListNode]:
+        length = 0
+        node = head
+        while node:
+            length += 1
+            node = node.next
+
+        dummy = ListNode(None, head)
+        node = dummy
+        for _ in range(length - n):
+            node = node.next
+
+        node.next = node.next.next
+        return dummy.next

same-tree/hu6r1s.py

@@ -0,0 +1,15 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
+        if not p and not q:
+            return True
+        if not p or not q:
+            return False
+        if p.val != q.val:
+            return False
+        return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)