Binary tree

Question 1

Binary Tree maximum path sum

Answer 1

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Question 2

Height of Binary Tree after Subtree Removal Queries - G

Answer 2

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Question 3

Number of good leaf nodes pairs

Answer 3

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Question 4

Diameter of binary tree

Answer 4

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Question 5

Validate binary search tree

Answer 5

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Question 6

Serialize and deserialize N-ary tree

Answer 6

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Question 7

Serialize and deserialize binary tree

Answer 7

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Question 8

Equal tree partition

Answer 8

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Question 9

Symmetric tree

Answer 9

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Question 10

Count nodes equal to average of subtree

Answer 10

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Question 11

Delete nodes and return forest

Answer 11

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Question 12

Construct string from binary tree

Answer 12

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Question 13

Lowest common ancestor

Answer 13

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Question 14

Lowest common ancestor - when nodes may not may not exist

Answer 14

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Question 15

Lowest common ancestor - with pointer to parent and nodes as input

Answer 15

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Question 16

Lowest common ancestor - when N nodes all exist

Answer 16

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Question 17

Construct binary from preorder and in order traversal

Answer 17

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Question 18

Find largest value in each tree row

Answer 18

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Question 19

Binary tree right side view

Answer 19

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Question 20

Binary tree vertical order traversal

Answer 20

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Question 21

Binary tree level order traversal

Answer 21

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Question 22

Binary tree level order traversal - bottom up

Answer 22

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Question 23

Binary tree preorder

Answer 23

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Question 24

Binary tree in order

Answer 24

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Question 25

Binary tree post order

Answer 25

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Question 26

Convert binary search tree to sorted double linked list

Answer 26

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Question 27

Flatten binary tree to linked list preorder

Answer 27

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Question 28

K-th smallest value in BST

Answer 28

You know it, in order traversal

Question 29

Delete node in a BST

Answer 29

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Question 30

Delete subtree that sums to 0 and return number of nodes that remain

Answer 30

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Question 31

Invert binary tree - the mirror of tree

Answer 31

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Question 32

Binary tree return all paths to leaves

Answer 32

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Question 33

Collect leaves and remove leaves of binary tree - G

Answer 33

You know it, tree height

Question 34

Reverse odd levels of binary tree

Answer 34

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Question 35

Print binary tree in matrix

Answer 35

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Question 36

Find mode in binary search tree (the most frequently occurred element)

Answer 36

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Question 37

Sum of distances for all nodes in tree - G

Answer 37

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Question 38

Find number of coins to place in tree nodes - G

Answer 38

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Question 39

House Robber III - cannot take directly linked house

Answer 39

You may not know it well

Question 40

Construct binary tree from string with parentheses - F

Answer 40

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Question 41

Binary Tree Vertical Traversal - sorted by value in the same row

Question 42

Binary search tree iterator

Answer 42

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Question 43

Undirected graph valid tree

Answer 43

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Question 44

Minimum height trees - G, F

Answer 44

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Question 45

Boundary of binary tree - F

Answer 45

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Question 46

Merge two binary trees

Answer 46

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Question 47

Average of levels in binary tree

Answer 47

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Question 48

Longest univalue path in binary tree - F

Answer 48

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Question 49

Smallest subtree with all the deepest nodes - F

Answer 49

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Question 50

All nodes with distance K from a target node (not root) in binary tree

Answer 50

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Question 51

Add nodes into complete binary tree

Answer 51

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Question 52

Range sum of binary search tree

Answer 52

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Question 53

Construct binary search tree from preorder traversal - F

Answer 53

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Question 54

Recover a tree from preorder traversal with dash - F

Answer 54

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Question 55

Undirected tree diameter - F

Answer 55

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Question 56

Balance binary search tree

Answer 56

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Question 57

Check if a binary tree is balanced

Answer 57

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Question 58

Closest binary search tree value

Answer 58

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Question 59

Populate next right pointers in each node - G

Answer 59

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Question 60

Sum root to leaf numbers - F

Answer 60

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Question 61

Diameter of N-ary tree - F

Answer 61

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Question 62

Maximum level sum of binary tree - F

Answer 62

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Question 63

Binary tree zigzag level traversal - G, F

Answer 63

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Question 64

Check completeness of binary tree - F

Answer 64

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Question 65

Minimum time to collect all apples in tree - F

Answer 65

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Question 66

Binary tree path sum equal to target

Answer 66

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