117 Populating Next Right Pointers in Each Node II

Author: gavinfish

117 Populating Next Right Pointers in Each Node II.py

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+'''
+Follow up for problem "Populating Next Right Pointers in Each Node".
+
+What if the given tree could be any binary tree? Would your previous solution still work?
+
+Note:
+
+You may only use constant extra space.
+For example,
+Given the following binary tree,
+         1
+       /  \
+      2    3
+     / \    \
+    4   5    7
+After calling your function, the tree should look like:
+         1 -> NULL
+       /  \
+      2 -> 3 -> NULL
+     / \    \
+    4-> 5 -> 7 -> NULL
+'''
+
+# Definition for binary tree with next pointer.
+class TreeLinkNode(object):
+    def __init__(self, x):
+        self.val = x
+        self.left = None
+        self.right = None
+        self.next = None
+
+
+class Solution(object):
+    def connect(self, root):
+        """
+        :type root: TreeLinkNode
+        :rtype: nothing
+        """
+        prekid = kid = TreeLinkNode(0)
+        while root:
+            while root:
+                kid.next = root.left
+                kid = kid.next or kid
+                kid.next = root.right
+                kid = kid.next or kid
+                root = root.next
+            root, kid = prekid.next, prekid
+
+
+if __name__ == "__main__":
+    None