Add problem 2924: Find Champion II

Author: EFanZh

src/lib.rs

@@ -2015,6 +2015,7 @@ pub mod problem_2917_find_the_k_or_of_an_array;
 pub mod problem_2918_minimum_equal_sum_of_two_arrays_after_replacing_zeros;
 pub mod problem_2919_minimum_increment_operations_to_make_array_beautiful;
 pub mod problem_2923_find_champion_i;
+pub mod problem_2924_find_champion_ii;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2924_find_champion_ii/greedy.rs

@@ -0,0 +1,33 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn find_champion(n: i32, edges: Vec<Vec<i32>>) -> i32 {
+        let mut lost = vec![false; n as u32 as usize].into_boxed_slice();
+
+        edges.into_iter().for_each(|edge| lost[edge[1] as u32 as usize] = true);
+
+        if lost.iter().filter(|&&lost| !lost).count() == 1 {
+            lost.iter().position(|&lost| !lost).unwrap() as _
+        } else {
+            -1
+        }
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn find_champion(n: i32, edges: Vec<Vec<i32>>) -> i32 {
+        Self::find_champion(n, edges)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2924_find_champion_ii/mod.rs

@@ -0,0 +1,21 @@
+pub mod greedy;
+
+pub trait Solution {
+    fn find_champion(n: i32, edges: Vec<Vec<i32>>) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ((3, &[[0, 1], [1, 2]] as &[_]), 0),
+            ((4, &[[0, 2], [1, 3], [1, 2]]), -1),
+        ];
+
+        for ((n, edges), expected) in test_cases {
+            assert_eq!(S::find_champion(n, edges.iter().map(Vec::from).collect()), expected,);
+        }
+    }
+}