82 lines
1.9 KiB
Markdown
82 lines
1.9 KiB
Markdown
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https://www.codewars.com/kata/52a78825cdfc2cfc87000005/fork/python
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# Instructions
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Given a mathematical expression as a string you must return the result as a number.
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## Numbers
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Number may be both whole numbers and/or decimal numbers. The same goes for the returned result.
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## Operators
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You need to support the following mathematical operators:
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* Multiplication `*`
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* Division `/` (as floating point division)
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* Addition `+`
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* Subtraction `-`
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Operators are always evaluated from left-to-right, and `*` and `/` must be evaluated before `+` and `-`.
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## Parentheses
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You need to support multiple levels of nested parentheses, ex. `(2 / (2 + 3.33) * 4) - -6`
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## Whitespace
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There may or may not be whitespace between numbers and operators.
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An addition to this rule is that the minus sign (`-`) used for negating numbers and parentheses will *never* be separated by whitespace. I.e all of the following are **valid** expressions.
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```
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1-1 // 0
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1 -1 // 0
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1- 1 // 0
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1 - 1 // 0
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1- -1 // 2
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1 - -1 // 2
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1--1 // 2
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6 + -(4) // 2
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6 + -( -4) // 10
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```
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And the following are **invalid** expressions
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```
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1 - - 1 // Invalid
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1- - 1 // Invalid
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6 + - (4) // Invalid
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6 + -(- 4) // Invalid
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```
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## Validation
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You do not need to worry about validation - you will only receive **valid** mathematical expressions following the above rules.
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## Restricted APIs
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```if:javascript
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NOTE: Both `eval` and `Function` are disabled.
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```
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```if:php
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NOTE: `eval` is disallowed in your solution.
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```
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```if:python
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NOTE: `eval` and `exec` are disallowed in your solution.
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```
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```if:clojure
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NOTE: `eval` and `import` are disallowed in your solution.
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```
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```if:java
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NOTE: To keep up the difficulty of the kata, use of some classes and functions is disallowed. Their names cannot appear in the solution file, even in comments and variable names.
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```
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```if:rust
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NOTE: `std::process::Command` is disallowed in your solution.
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```
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