Add problem 3024: Type of Triangle

Author: EFanZh

src/lib.rs

@@ -2051,6 +2051,7 @@ pub mod problem_3014_minimum_number_of_pushes_to_type_word_i;
 pub mod problem_3016_minimum_number_of_pushes_to_type_word_ii;
 pub mod problem_3019_number_of_changing_keys;
 pub mod problem_3021_alice_and_bob_playing_flower_game;
+pub mod problem_3024_type_of_triangle;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_3024_type_of_triangle/mathematical.rs

@@ -0,0 +1,56 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::mem;
+
+impl Solution {
+    pub fn triangle_type(nums: Vec<i32>) -> String {
+        const BUFFER: &str = "isoscelescalenequilateral";
+
+        let isosceles = &BUFFER[..9];
+        let scalene = &BUFFER[8..15];
+        let equilateral = &BUFFER[14..];
+        let [mut a, mut b, mut c] = <[_; 3]>::map(nums.try_into().ok().unwrap(), i32::cast_unsigned);
+
+        'block: {
+            let max = if b > a {
+                if c > b { &mut c } else { &mut b }
+            } else if c > a {
+                &mut c
+            } else {
+                break 'block;
+            };
+
+            mem::swap(&mut a, max);
+        }
+
+        String::from(if b + c > a {
+            if a == b {
+                if a == c { equilateral } else { isosceles }
+            } else if a == c || b == c {
+                isosceles
+            } else {
+                scalene
+            }
+        } else {
+            "none"
+        })
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn triangle_type(digits: Vec<i32>) -> String {
+        Self::triangle_type(digits)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3024_type_of_triangle/mod.rs

@@ -0,0 +1,23 @@
+pub mod mathematical;
+
+pub trait Solution {
+    fn triangle_type(digits: Vec<i32>) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (&[3, 3, 3] as &[_], "equilateral"),
+            (&[3, 4, 5], "scalene"),
+            (&[9, 4, 9], "isosceles"),
+            (&[5, 3, 8], "none"),
+        ];
+
+        for (digits, expected) in test_cases {
+            assert_eq!(S::triangle_type(digits.to_vec()), expected);
+        }
+    }
+}