Initial commit

collatz/.gitignore

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+/target

collatz/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "collatz"
+version = "0.1.0"

collatz/Cargo.toml

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

collatz/src/main.rs

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+/// Determine the length of the collatz sequence beginning at `n`.
+fn collatz_length(mut n: i32) -> u32 {
+    let mut i: u32 = 0;
+    loop {
+        i = i+1;
+        if n == 1 {
+            break
+        } else if n % 2 == 0 {
+            n = n / 2;
+        } else {
+            n = 3 * n + 1;
+        }
+    }
+    return i;
+}
+
+#[test]
+fn test_collatz_length() {
+    assert_eq!(collatz_length(11), 15);
+}
+
+fn main() {
+    println!("Length: {}", collatz_length(11));
+}

geometry/.gitignore

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+/target

geometry/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "geometry"
+version = "0.1.0"

geometry/Cargo.toml

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

geometry/src/main.rs

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+// Calculate the magnitude of a vector by summing the squares of its coordinates
+// and taking the square root. Use the `sqrt()` method to calculate the square
+// root, like `v.sqrt()`.
+
+fn magnitude(v: &[f64; 3]) -> f64 {
+    let mut r: f64 = 0.0;
+    for x in v {
+        r += x.powi(2);
+    }
+    r.sqrt()
+}
+
+// Normalize a vector by calculating its magnitude and dividing all of its
+// coordinates by that magnitude.
+
+fn normalize(v: &mut [f64; 3]) -> &[f64; 3] {
+    let mag = magnitude(v);
+    for elm in 0..v.len() {
+        v[elm] /= mag;
+    }
+    v
+}
+
+// Use the following `main` to test your work.
+
+fn main() {
+    println!(
+        "Magnitude of a unit vector: {}",
+        magnitude(&[0.0, 1.0, 0.0])
+    );
+
+    let mut v = [1.0, 2.0, 9.0];
+    println!("Magnitude of {v:?}: {}", magnitude(&v));
+    normalize(&mut v);
+    println!("Magnitude of {v:?} after normalization: {}", magnitude(&v));
+}

nest_array/.gitignore

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+/target

nest_array/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "nest_array"
+version = "0.1.0"

nest_array/Cargo.toml

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

nest_array/src/main.rs

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+// TODO: remove this when you're done with your implementation.
+#![allow(unused_variables, dead_code)]
+
+fn transpose(matrix: [[i32; 3]; 3]) -> [[i32; 3]; 3] {
+    let mut t = [[0; 3]; 3];
+    for row in 0..3 {
+        for column in 0..3 {
+            t[column][row] = matrix[row][column];
+        }
+    }
+    return t;
+}
+
+#[test]
+fn test_transpose() {
+    let matrix = [
+        [101, 102, 103], //
+        [201, 202, 203],
+        [301, 302, 303],
+    ];
+    let transposed = transpose(matrix);
+    assert_eq!(
+        transposed,
+        [
+            [101, 201, 301], //
+            [102, 202, 302],
+            [103, 203, 303],
+        ]
+    );
+}
+
+fn main() {
+    let matrix = [
+        [101, 102, 103], // <-- the comment makes rustfmt add a newline
+        [201, 202, 203],
+        [301, 302, 303],
+    ];
+
+    println!("matrix: {:#?}", matrix);
+    let transposed = transpose(matrix);
+    println!("transposed: {:#?}", transposed);
+}