Given a string str that contains a ternary expression which may be nested. The task is to convert the given ternary expression to a binary tree and return the root.
Input: str = "a?b:c" Output: a b c a / \ b c The preorder traversal of the above tree is a b c. Input: str = "a?b?c:d:e" Output: a b c d e a / \ b e / \ c d
Approach: This is a stack-based approach to the given problem. Since the ternary operator has associativity from right-to-left, the string can be traversed from right to left. Take the letters one by one skipping the letters ‘?’ and ‘:’ as these letters are used to decide whether the current letter (alphabet [a to z]) will go into the stack or be used to pop the top 2 elements from the top of the stack to make them the children of the current letter which is then itself pushed into the stack. This forms the tree in a bottom-up manner and the last remaining element in the stack after the entire string is processed is the root of the tree.
Below is the implementation of the above approach:
a b c d e
Time Complexity: O(n)
- Convert Ternary Expression to a Binary Tree
- Minimum swap required to convert binary tree to binary search tree
- Convert a Binary Tree to Threaded binary tree | Set 2 (Efficient)
- Convert a Binary Tree to Threaded binary tree | Set 1 (Using Queue)
- Convert an arbitrary Binary Tree to a tree that holds Children Sum Property
- Convert a given Binary tree to a tree that holds Logical AND property
- Convert a given Binary tree to a tree that holds Logical OR property
- Convert a Binary Tree into its Mirror Tree
- Postorder traversal of Binary Tree without recursion and without stack
- Print leaf nodes in binary tree from left to right using one stack
- Reverse alternate levels of a perfect binary tree using Stack
- Inorder Non-threaded Binary Tree Traversal without Recursion or Stack
- Convert left-right representation of a binary tree to down-right
- Find maximum and minimum element in binary tree without using recursion or stack or queue
- Building Expression tree from Prefix Expression
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