100 exercises to learn Rust

exercises/06_ticket_management/02_vec/Cargo.toml

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+[package]
+name = "vec"
+version = "0.1.0"
+edition = "2021"

exercises/06_ticket_management/02_vec/src/lib.rs

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+// Given a number `n`, return the `n+1`th number in the Fibonacci sequence.
+//
+// The Fibonacci sequence is defined as follows:
+//
+// - The first number of the sequence is 0.
+// - The second number of the sequence is 1.
+// - Every subsequent number is the sum of the two preceding numbers.
+//
+// So the sequence goes: 0, 1, 1, 2, 3, 5, 8, 13, 21, and so on.
+//
+// We expect `fibonacci(0)` to return `0`, `fibonacci(1)` to return `1`,
+// `fibonacci(2)` to return `1`, and so on.
+pub fn fibonacci(n: u32) -> u32 {
+    // TODO: implement the `fibonacci` function
+    //
+    // Hint: use a `Vec` to memoize the results you have already calculated
+    // so that you don't have to recalculate them several times.
+    todo!()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::fibonacci;
+
+    #[test]
+    fn first() {
+        assert_eq!(fibonacci(0), 0);
+    }
+
+    #[test]
+    fn second() {
+        assert_eq!(fibonacci(1), 1);
+    }
+
+    #[test]
+    fn third() {
+        assert_eq!(fibonacci(2), 1);
+    }
+
+    #[test]
+    fn tenth() {
+        assert_eq!(fibonacci(10), 55);
+    }
+
+    #[test]
+    fn thirthieth() {
+        assert_eq!(fibonacci(30), 832040);
+    }
+}