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Multi-phase polymorphic pipeline with traits
Rust
Hard
traits
Task «Multi-phase polymorphic pipeline with traits»
Implement a system of traits `Stage`, `Pipeline`, and `Transform` that allows building data processing pipelines. The `Stage` trait defines the method `process(&self, input: i32) -> i32`. The `Pipeline` trait defines the method `run(&self, stages: Vec<Box<dyn Stage>>, input: i32) -> i32`, which sequentially applies all stages. The `Transform` trait defines the method `transform(&self, value: i32) -> i32`, which can modify the value according to some rule. Implement the structures `AddStage`, `MultiplyStage`, `NegateStage`, each of which implements `Stage`. Also implement the structure `SimplePipeline`, which implements `Pipeline`. Then write a function that takes a string with commands (`add`, `mul`, `neg`) and numbers, creates the corresponding stages, runs the pipeline with an initial value of 0, and outputs the result. Commands are space-separated: `add 5 mul 2 neg`. Constraints: input value is `i32`, the result is guaranteed to fit into `i32`.
Input Format
A string with commands and numbers separated by spaces. For example: 'add 5 mul 2 neg'.
Output Format
An integer is the result of processing an initial value of 0 through a pipeline of stages.
Examples
Example 1
INPUT
add 5 mul 2 neg
OUTPUT
-10
Example 2
INPUT
mul 3 add 10 neg
OUTPUT
-10
Example 3
INPUT
5
1 2 3 4 5
OUTPUT
0
Example 4
INPUT
add 100 mul 0
OUTPUT
0
Example 5
INPUT
4
OUTPUT
0
main.rs