added python solutions to some problems

Author: Kurt-Yu

README.md

@@ -8,6 +8,7 @@ LeetCode
 
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
+|958|[Check Completeness of a Binary Tree](https://leetcode.com/problems/check-completeness-of-a-binary-tree/) | [Python](./algorithms/python/CheckCompletenessOfABinaryTree/isCompleteTree.py)|Medium|
 |951|[Flip Equivalent Binary Trees](https://leetcode.com/problems/flip-equivalent-binary-trees/) | [Python](./algorithms/python/FlipEquivalentBinaryTrees/flipEquiv.py)|Medium|
 |859|[Buddy Strings](https://leetcode.com/problems/buddy-strings/description/) | [C++](./algorithms/cpp/buddyStrings/BuddyStrings.cpp)|Easy|
 |858|[Mirror Reflection](https://leetcode.com/problems/mirror-reflection/description/) | [C++](./algorithms/cpp/mirrorReflection/MirrorReflection.cpp)|Medium|
@@ -20,6 +21,7 @@ LeetCode
 |671|[Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/) | [Python](./algorithms/python/SecondMinimumNodeInABinaryTree/findSecondMinimumValue.py)|Easy|
 |662|[Maximum Width of Binary Tree](https://leetcode.com/problems/maximum-width-of-binary-tree/) | [Python](./algorithms/python/MaximumWidthOfBinaryTree/widthOfBinaryTree.py)|Medium|
 |655|[Print Binary Tree](https://leetcode.com/problems/print-binary-tree/) | [Python](./algorithms/python/PrintBinaryTree/printTree.py)|Medium|
+|652|[Find Duplicate Subtrees](https://leetcode.com/problems/find-duplicate-subtrees/) | [Python](./algorithms/python/FindDuplicateSubtrees/findDuplicateSubtrees.py)|Medium|
 |643|[Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i/description/) | [C++](./algorithms/cpp/maximumAverageSubarray/MaximumAverageSubarray.I.cpp)|Easy|
 |623|[Add One Row to Tree](https://leetcode.com/problems/add-one-row-to-tree/) | [Python](./algorithms/python/AddOneRowToTree/addOneRow.py)|Medium|
 |572|[Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/) | [Python](./algorithms/python/SubtreeOfAnotherTree/isSubtree.py)|Easy|
@@ -234,7 +236,7 @@ LeetCode
 |119|[Pascal's Triangle II](https://oj.leetcode.com/problems/pascals-triangle-ii/)| [C++](./algorithms/cpp/pascalTriangle/pascalTriangle.II.cpp)|Easy|
 |118|[Pascal's Triangle](https://oj.leetcode.com/problems/pascals-triangle/)| [C++](./algorithms/cpp/pascalTriangle/pascalTriangle.cpp)|Easy|
 |117|[Populating Next Right Pointers in Each Node II](https://oj.leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/)| [C++](./algorithms/cpp/populatingNextRightPointersInEachNode/populatingNextRightPointersInEachNode.II.cpp)|Hard|
-|116|[Populating Next Right Pointers in Each Node](https://oj.leetcode.com/problems/populating-next-right-pointers-in-each-node/)| [C++](./algorithms/cpp/populatingNextRightPointersInEachNode/populatingNextRightPointersInEachNode.cpp)|Medium|
+|116|[Populating Next Right Pointers in Each Node](https://oj.leetcode.com/problems/populating-next-right-pointers-in-each-node/)| [C++](./algorithms/cpp/populatingNextRightPointersInEachNode/populatingNextRightPointersInEachNode.cpp), [Python](./algorithms/python/PopulatingNextRightPointersInEachNode/connect.py)|Medium|
 |115|[Distinct Subsequences](https://oj.leetcode.com/problems/distinct-subsequences/)| [C++](./algorithms/cpp/distinctSubsequences/distinctSubsequences.cpp)|Hard|
 |114|[Flatten Binary Tree to Linked List](https://oj.leetcode.com/problems/flatten-binary-tree-to-linked-list/)| [C++](./algorithms/cpp/flattenBinaryTreeToLinkedList/flattenBinaryTreeToLinkedList.cpp), [Python](./algorithms/python/FlattenBinaryTreeToLinkedList/flatten.py)|Medium|
 |113|[Path Sum II](https://oj.leetcode.com/problems/path-sum-ii/)| [C++](./algorithms/cpp/pathSum/pathSum.II.cpp)|Medium|
@@ -244,8 +246,8 @@ LeetCode
 |109|[Convert Sorted List to Binary Search Tree](https://oj.leetcode.com/problems/convert-sorted-list-to-binary-search-tree/)| [C++](./algorithms/cpp/convertSortedListToBinarySearchTree/convertSortedListToBinarySearchTree.cpp)|Medium|
 |108|[Convert Sorted Array to Binary Search Tree](https://oj.leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)| [C++](./algorithms/cpp/convertSortedArrayToBinarySearchTree/convertSortedArrayToBinarySearchTree.cpp)|Medium|
 |107|[Binary Tree Level Order Traversal II](https://oj.leetcode.com/problems/binary-tree-level-order-traversal-ii/)| [C++](./algorithms/cpp/binaryTreeLevelOrderTraversal/binaryTreeLevelOrderTraversal.II.cpp)|Easy|
-|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://oj.leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/)| [C++](./algorithms/cpp/constructBinaryTreeFromInorderAndPostorderTraversal/constructBinaryTreeFromInorderAndPostorderTraversal.cpp)|Medium|
-|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://oj.leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)| [C++](./algorithms/cpp/constructBinaryTreeFromPreorderAndInorderTraversal/constructBinaryTreeFromPreorderAndInorderTraversal.cpp)|Medium|
+|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://oj.leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/)| [C++](./algorithms/cpp/constructBinaryTreeFromInorderAndPostorderTraversal/constructBinaryTreeFromInorderAndPostorderTraversal.cpp), [Python](./algorithms/python/ConstructBinaryTreeFromInorderAndPostorderTraversal/buildTree.py)|Medium|
+|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://oj.leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)| [C++](./algorithms/cpp/constructBinaryTreeFromPreorderAndInorderTraversal/constructBinaryTreeFromPreorderAndInorderTraversal.cpp), [Python](./algorithms/python/ConstructBinaryTreeFromPreorderAndInorderTraversal/buildTree.py)|Medium|
 |104|[Maximum Depth of Binary Tree](https://oj.leetcode.com/problems/maximum-depth-of-binary-tree/)| [C++](./algorithms/cpp/maximumDepthOfBinaryTree/maximumDepthOfBinaryTree.cpp), [Java](./algorithms/java/src/maximumDepthOfBinaryTree/maximumDepthOfBinaryTree.java)|Easy|
 |103|[Binary Tree Zigzag Level Order Traversal](https://oj.leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)| [C++](./algorithms/cpp/binaryTreeZigzagLevelOrderTraversal/binaryTreeZigzagLevelOrderTraversal.cpp), [Python](./algorithms/python/BinaryTreeZigzagLevelOrderTraversal/zigzagLevelOrder.py)|Medium|
 |102|[Binary Tree Level Order Traversal](https://oj.leetcode.com/problems/binary-tree-level-order-traversal/)| [C++](./algorithms/cpp/binaryTreeLevelOrderTraversal/binaryTreeLevelOrderTraversal.cpp), [Java](./algorithms/java/src/binaryTreeLevelOrderTraversal/binaryTreeLevelOrderTraversal.java)|Easy|

algorithms/python/CheckCompletenessOfABinaryTree/isCompleteTree.py

@@ -0,0 +1,14 @@
+def isCompleteTree(self, root):
+    stack = [[(root, 0)]]
+    layer = 0
+    while True:
+        children = []
+        for node, value in stack[-1]:
+            if node.left: children.append((node.left, 2 * value))
+            if node.right: children.append((node.right, 2 * value + 1))
+            if node.right and not node.left: return False
+        if not children: break
+        if len(stack[-1]) != pow(2, layer): return False
+        stack.append(children)
+        layer += 1
+    return len(stack[-1]) == stack[-1][-1][1] + 1

algorithms/python/ConstructBinaryTreeFromInorderAndPostorderTraversal/buildTree.py

@@ -0,0 +1,7 @@
+def buildTree(self, inorder, postorder):
+    if inorder:
+        i = inorder.index(postorder.pop())
+        root = TreeNode(inorder[i])
+        root.right = self.buildTree(inorder[i+1:], postorder)
+        root.left = self.buildTree(inorder[:i], postorder)
+        return root

algorithms/python/ConstructBinaryTreeFromPreorderAndInorderTraversal/buildTree.py

@@ -0,0 +1,7 @@
+def buildTree(self, preorder, inorder):
+    if inorder:
+        i = inorder.index(preorder.pop(0))
+        root = TreeNode(inorder[i])
+        root.left = self.buildTree(preorder, inorder[:i])
+        root.right = self.buildTree(preorder, inorder[i+1:])
+        return root

algorithms/python/FindDuplicateSubtrees/findDuplicateSubtrees.py

@@ -0,0 +1,11 @@
+def findDuplicateSubtrees(self, root):
+    nodes = collections.defaultdict(list)
+    
+    def helper(root):
+        if not root: return 'None'
+        struct = '%s,%s,%s' % (str(root.val), helper(root.left), helper(root.right))
+        nodes[struct].append(root)
+        return struct
+    
+    helper(root)
+    return [nodes[struct][0] for struct in nodes if len(nodes[struct]) > 1]

algorithms/python/PopulatingNextRightPointersInEachNode/connect.py

@@ -0,0 +1,9 @@
+def connect(self, root):
+    if not root: return
+    stack = [[root]]
+    while True:
+        children = [child for node in stack[-1] for child in (node.left, node.right) if child]
+        if not children: break
+        stack.append(children)
+        for i in range(len(children) - 1):
+            children[i].next = children[i+1]