markov chain exercise skeleton

edu/exercises/markov/weather-chain/.rust-version

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+nightly

edu/exercises/markov/weather-chain/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "random"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d62d9cce151a97168445d78542558d3bddf6cf99f283c475f2eaf5cc14c364a"
+
+[[package]]
+name = "weather-chain"
+version = "0.1.0"
+dependencies = [
+ "random",
+]

edu/exercises/markov/weather-chain/Cargo.toml

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+[package]
+name = "weather-chain"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+rand = "0.10.0"

edu/exercises/markov/weather-chain/src/main.rs

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+use rand::Rng;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum Weather { Sunny, Rainy }
+
+struct WeatherChain {
+    /// transition[current][next] = probability
+    transition: [[f64; 2]; 2],
+}
+
+impl WeatherChain {
+    fn step(&self, current: Weather, rng: &mut impl Rng) -> Weather { todo!() }
+    fn simulate(&self, start: Weather, steps: usize, rng: &mut impl Rng) -> Vec<Weather> { todo!() }
+}
+
+fn main() {
+    todo!()
+}