fix: Add Challenge 63 (Issue 72)

src/SUMMARY.md

@@ -64,4 +64,5 @@
   - [Challenge 60](./challenges/challenge-60.md)
   - [Challenge 61](./challenges/challenge-61.md)
   - [Challenge 62](./challenges/challenge-62.md)
+  - [Challenge 63](./challenges/challenge-63.md)
 - [Resources](./resources.md)

src/challenges/challenge-63.md

@@ -0,0 +1,228 @@
+# Challenge 63
+
+### Number Spiral
+
+Given a positive integer n, generate an n x n spiral matrix filled with numbers from 1 to n² in a clockwise spiral pattern, starting from the top-left corner.
+
+Your function `generate_spiral` should return the matrix as a vector of vectors.
+
+The spiral moves right, down, left, and up, filling the matrix layer by layer.
+
+```rust,editable
+    assert_eq!(generate_spiral(0), Vec::<Vec<i32>>::new());
+    assert_eq!(generate_spiral(1), vec![vec![1]]);
+    assert_eq!(generate_spiral(3), vec![vec![1, 2, 3], vec![8, 9, 4], vec![7, 6, 5]]);
+    assert_eq!(
+        generate_spiral(5),
+        vec![
+            vec![1, 2, 3, 4, 5],
+            vec![16, 17, 18, 19, 6],
+            vec![15, 24, 25, 20, 7],
+            vec![14, 23, 22, 21, 8],
+            vec![13, 12, 11, 10, 9]
+        ]
+    );
+```
+
+#### Write your solution below
+
+```rust,editable
+// Rust Bytes Issue 72: Number Spiral
+
+pub fn generate_spiral(n: i32) -> Vec<Vec<i32>> {
+    // your implementation goes here
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_n_1() {
+        assert_eq!(generate_spiral(1), vec![vec![1]]);
+    }
+
+    #[test]
+    fn test_n_2() {
+        assert_eq!(generate_spiral(2), vec![vec![1, 2], vec![4, 3]]);
+    }
+
+    #[test]
+    fn test_n_3() {
+        assert_eq!(
+            generate_spiral(3),
+            vec![vec![1, 2, 3], vec![8, 9, 4], vec![7, 6, 5]]
+        );
+    }
+
+    #[test]
+    fn test_n_0() {
+        assert_eq!(generate_spiral(0), Vec::<Vec<i32>>::new());
+    }
+
+    #[test]
+    fn test_n_negative() {
+        assert_eq!(generate_spiral(-1), Vec::<Vec<i32>>::new());
+    }
+
+    #[test]
+    fn test_n_4() {
+        assert_eq!(
+            generate_spiral(4),
+            vec![
+                vec![1, 2, 3, 4],
+                vec![12, 13, 14, 5],
+                vec![11, 16, 15, 6],
+                vec![10, 9, 8, 7]
+            ]
+        );
+    }
+
+    #[test]
+    fn test_n_5() {
+        assert_eq!(
+            generate_spiral(5),
+            vec![
+                vec![1, 2, 3, 4, 5],
+                vec![16, 17, 18, 19, 6],
+                vec![15, 24, 25, 20, 7],
+                vec![14, 23, 22, 21, 8],
+                vec![13, 12, 11, 10, 9]
+            ]
+        );
+    }
+
+    #[test]
+    fn test_n_20() {
+        let result = generate_spiral(20);
+        assert_eq!(result.len(), 20, "Matrix should have 20 rows");
+        assert_eq!(result[0].len(), 20, "Matrix should have 20 columns");
+        assert_eq!(result[0][0], 1, "Top-left corner should be 1");
+        assert_eq!(
+            result[19][19], 400,
+            "Bottom-right corner should be n² (400 for n=20)"
+        );
+        assert_eq!(
+            result[9][9], 181,
+            "Middle element should match spiral pattern"
+        );
+    }
+}
+```
+
+### Solution
+
+<details>
+<summary>Click to Show/Hide Solution</summary>
+
+```rust
+// Rust Bytes Issue 72: Number Spiral
+
+pub fn generate_spiral(n: i32) -> Vec<Vec<i32>> {
+    if n <= 0 {
+        return vec![];
+    }
+
+    let mut matrix = vec![vec![0; n as usize]; n as usize];
+    let (mut row, mut col) = (0, 0);
+    let (mut dr, mut dc) = (0, 1);
+
+    for i in 1..=(n * n) {
+        matrix[row as usize][col as usize] = i;
+        let next_row = row + dr;
+        let next_col = col + dc;
+
+        if next_row < 0
+            || next_row >= n
+            || next_col < 0
+            || next_col >= n
+            || matrix[next_row as usize][next_col as usize] != 0
+        {
+            (dr, dc) = (dc, -dr);
+        }
+
+        row += dr;
+        col += dc;
+    }
+
+    matrix
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_n_1() {
+        assert_eq!(generate_spiral(1), vec![vec![1]]);
+    }
+
+    #[test]
+    fn test_n_2() {
+        assert_eq!(generate_spiral(2), vec![vec![1, 2], vec![4, 3]]);
+    }
+
+    #[test]
+    fn test_n_3() {
+        assert_eq!(
+            generate_spiral(3),
+            vec![vec![1, 2, 3], vec![8, 9, 4], vec![7, 6, 5]]
+        );
+    }
+
+    #[test]
+    fn test_n_0() {
+        assert_eq!(generate_spiral(0), Vec::<Vec<i32>>::new());
+    }
+
+    #[test]
+    fn test_n_negative() {
+        assert_eq!(generate_spiral(-1), Vec::<Vec<i32>>::new());
+    }
+
+    #[test]
+    fn test_n_4() {
+        assert_eq!(
+            generate_spiral(4),
+            vec![
+                vec![1, 2, 3, 4],
+                vec![12, 13, 14, 5],
+                vec![11, 16, 15, 6],
+                vec![10, 9, 8, 7]
+            ]
+        );
+    }
+
+    #[test]
+    fn test_n_5() {
+        assert_eq!(
+            generate_spiral(5),
+            vec![
+                vec![1, 2, 3, 4, 5],
+                vec![16, 17, 18, 19, 6],
+                vec![15, 24, 25, 20, 7],
+                vec![14, 23, 22, 21, 8],
+                vec![13, 12, 11, 10, 9]
+            ]
+        );
+    }
+
+    #[test]
+    fn test_n_20() {
+        let result = generate_spiral(20);
+        assert_eq!(result.len(), 20, "Matrix should have 20 rows");
+        assert_eq!(result[0].len(), 20, "Matrix should have 20 columns");
+        assert_eq!(result[0][0], 1, "Top-left corner should be 1");
+        assert_eq!(
+            result[19][19], 400,
+            "Bottom-right corner should be n² (400 for n=20)"
+        );
+        assert_eq!(
+            result[9][9], 181,
+            "Middle element should match spiral pattern"
+        );
+    }
+}
+```
+
+</details>