Basic Calculator IV — LeetCode 770 Python Solution

The problem

Given an expression such as expression = "e + 8 - a + 5" and an evaluation map such as {"e": 1} (given in terms of evalvars = ["e"] and evalints = [1]), return a list of tokens representing the simplified expression, such as ["-1*a","14"] An expression alternates chunks and symbols, with a space separating each chunk and symbol. A chunk is either an expression in parentheses, a variable, or a non-negative integer.

Example

Input

expression = "e + 8 - a + 5", evalvars = ["e"], evalints = [1]

Output

["-1*a","14"]

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 770. Basic Calculator IV is filed here because LeetCode tags it Stack, which is the vocabulary this hub collects.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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