Binary Tree: Interview Questions and Practice Problems

Vivek Srivastava
Techie Delight

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A Binary Tree is a tree data structure in which each node has at most two children, which are referred to as the left child and the right child, and the topmost node in the tree is called the root.

In this post, we have listed out commonly asked interview questions that use binary tree:

  1. Inorder Tree Traversal
  2. Preorder Tree Traversal
  3. Postorder Tree Traversal
  4. Check if two binary trees are identical or not
  5. Print bottom view of a binary tree
  6. Print top view of a binary tree
  7. In-place convert a binary tree to its sum tree
  8. Determine whether the given binary tree nodes are cousins of each other
  9. Print cousins of a given node in a binary tree
  10. Check if a binary tree is a sum tree or not
  11. Combinations of words formed by replacing given numbers with corresponding alphabets
  12. Determine whether a binary tree is a subtree of another binary tree
  13. Find the diameter of a binary tree
  14. Check if a binary tree is symmetric or not
  15. Convert a binary tree to its mirror
  16. Determine if a binary tree can be converted to another by doing any number of swaps of children
  17. Find the Lowest Common Ancestor (LCA) of two nodes in a binary tree
  18. Print all paths from the root to leaf nodes of a binary tree
  19. Find ancestors of a given node in a binary tree
  20. Find distance between given pairs of nodes in a binary tree
  21. Find the diagonal sum of a binary tree
  22. Sink nodes containing zero to the bottom of a binary tree
  23. Convert a binary tree to a full tree by removing half nodes
  24. Truncate a binary tree to remove nodes that lie on a path having a sum less than `k`
  25. Find maximum sum root to leaf path in a binary tree
  26. Check if a binary tree is height-balanced or not
  27. Convert binary tree to Left-child right-sibling binary tree
  28. Print all paths from leaf to root node of a binary tree
  29. Iteratively print the leaf to root path for every leaf node in a binary tree
  30. Build a binary tree from a parent array
  31. Find all nodes at a given distance from leaf nodes in a binary tree
  32. Count all subtrees having the same value of nodes in a binary tree
  33. Find the maximum difference between a node and its descendants in a binary tree
  34. Find the maximum sum path between two leaves in a binary tree
  35. Construct a binary tree from inorder and preorder traversal
  36. Construct a binary tree from inorder and postorder traversals
  37. Construct a binary tree from inorder and level order sequence
  38. Construct a full binary tree from the preorder sequence with leaf node information
  39. Construct a full binary tree from a preorder and postorder sequence
  40. Find postorder traversal of a binary tree from its inorder and preorder sequence
  41. Set next pointer to the inorder successor of all nodes in a binary tree
  42. Find preorder traversal of a binary tree from its inorder and postorder sequence
  43. Find the difference between the sum of all nodes present at odd and even levels in a binary tree
  44. Clone a binary tree with random pointers
  45. Threaded Binary Tree — Overview and Implementation
  46. Determine if a binary tree satisfies the height-balanced property of a red–black tree
  47. Construct an ancestor matrix from a binary tree
  48. Find all possible binary trees having the same inorder traversal
  49. Perform boundary traversal on a binary tree
  50. Check if each node of a binary tree has exactly one child
  51. Evaluate a Binary Expression Tree
  52. Construction of an expression tree
  53. Fix children-sum property in a binary tree
  54. Maximum path sum in a binary tree
  55. Create a mirror of an m–ary tree
  56. Print a two-dimensional view of a binary tree
  57. Construct a binary tree from an ancestor matrix
  58. Determine whether a given binary tree is a BST or not
  59. Find inorder successor for the given key in a BST
  60. Fix a binary tree that is only one swap away from becoming a BST
  61. Find the size of the largest BST in a binary tree
  62. Print binary tree structure with its contents in C++
  63. Maximum Independent Set Problem
  64. Huffman Coding Compression Algorithm
  65. Construct a Cartesian tree from an inorder traversal
  66. Calculate the height of a binary tree with leaf nodes forming a circular doubly linked list
  67. Link nodes present in each level of a binary tree in the form of a linked list
  68. Convert a ternary tree to a doubly-linked list
  69. Extract leaves of a binary tree into a doubly-linked list
  70. Find the vertical sum of a binary tree
  71. In-place convert a binary tree to a doubly-linked list
  72. Check whether the leaf traversal of given binary trees is the same or not
  73. Efficiently print all nodes between two given levels in a binary tree
  74. Calculate the height of a binary tree
  75. Delete a binary tree
  76. Level order traversal of a binary tree
  77. Spiral order traversal of a binary tree
  78. Reverse level order traversal of a binary tree
  79. Print all nodes of a perfect binary tree in a specific order
  80. Print left view of a binary tree
  81. Find the next node at the same level as the given node in a binary tree
  82. Check if a binary tree is a complete binary tree or not
  83. Print diagonal traversal of a binary tree
  84. Print corner nodes of every level in a binary tree
  85. Invert Binary Tree
  86. Convert a binary tree into a doubly-linked list in spiral order
  87. Check if a binary tree is a min-heap or not
  88. Invert alternate levels of a perfect binary tree
  89. Perform vertical traversal of a binary tree
  90. Compute the maximum number of nodes at any level in a binary tree
  91. Print right view of a binary tree
  92. Find the minimum depth of a binary tree
  93. Depth-First Search (DFS) vs Breadth-First Search (BFS)
  94. Print nodes of a binary tree in vertical order

Thanks for reading.

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