Wrote program for Day 10

https://en.wikipedia.org/wiki/Catalan_number

Week-02/Day-10_Unique-Binary-Search-Trees/day10/Cargo.toml

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+[package]
+name = "day10"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-02/Day-10_Unique-Binary-Search-Trees/day10/src/lib.rs

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+pub fn catalan_number(n: u8) -> usize {
+    let mut result = 1f64;
+
+    for k in 2..=n {
+        result *= (n as f64 + k as f64) / k as f64;
+    }
+
+    result.round() as usize
+}

Week-02/Day-10_Unique-Binary-Search-Trees/day10/src/main.rs

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+use std::io::{self, Write};
+
+use day10::catalan_number;
+
+fn main() {
+    let mut buffer = String::new();
+
+    print!("Insert n: ");
+    io::stdout().flush().expect("Failed to flush stdout.");
+
+    io::stdin()
+        .read_line(&mut buffer)
+        .expect("Failed to read from stdin.");
+
+    let n: u8 = buffer
+        .trim()
+        .parse()
+        .expect("The input is not a positive integer");
+
+    println!(
+        "The number of structurally unique BST's that store values from 1 to n is {}",
+        catalan_number(n)
+    );
+}

Week-02/Day-10_Unique-Binary-Search-Trees/day10/tests/example.rs

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+use day10::catalan_number;
+
+#[test]
+fn example() {
+    assert_eq!(catalan_number(3), 5);
+}
+
+#[test]
+fn examplu() {
+    let array = [1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786];
+    for (i, a) in array.into_iter().enumerate() {
+        assert_eq!(catalan_number(i as u8), a);
+    }
+}