Leetcode Problem 770. Basic Calculator IV
Leetcode Solutions
Expression Parsing and Evaluation with Abstract Syntax Tree
- Parse the expression into an abstract syntax tree (AST).
- Perform a depth-first traversal of the AST.
- During traversal, evaluate each node:
- If it's an integer, return its value.
- If it's a variable, return its value from the evaluation map or the variable itself if not in the map.
- If it's an operation, recursively evaluate the left and right subtrees and combine the results according to the operation.
- After evaluating the AST, you will have a list of terms with coefficients and variables.
- Sort the terms by degree and lexicographic order.
- Format the terms into strings, ensuring that coefficients are placed correctly.
- Return the formatted list of terms as the final result.
Tokenization and Recursive Descent Parsing
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