Add problem 3285: Find Indices of Stable Mountains

Author: EFanZh

src/lib.rs

@@ -2169,6 +2169,7 @@ pub mod problem_3275_k_th_nearest_obstacle_queries;
 pub mod problem_3280_convert_date_to_binary;
 pub mod problem_3281_maximize_score_of_numbers_in_ranges;
 pub mod problem_3282_reach_end_of_array_with_max_score;
+pub mod problem_3285_find_indices_of_stable_mountains;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 
 #[cfg(test)]

src/problem_3285_find_indices_of_stable_mountains/iterative.rs

@@ -0,0 +1,43 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn stable_mountains(height: Vec<i32>, threshold: i32) -> Vec<i32> {
+        let mut height = height;
+        let mut prev = 0;
+        let mut i = -1;
+
+        height.retain_mut(|slot| {
+            i += 1;
+
+            let keep = prev > threshold;
+
+            prev = *slot;
+
+            if keep {
+                *slot = i;
+            }
+
+            keep
+        });
+
+        height
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn stable_mountains(height: Vec<i32>, threshold: i32) -> Vec<i32> {
+        Self::stable_mountains(height, threshold)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3285_find_indices_of_stable_mountains/mod.rs

@@ -0,0 +1,26 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn stable_mountains(height: Vec<i32>, threshold: i32) -> Vec<i32>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+    use crate::test_utilities;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ((&[1, 2, 3, 4, 5] as &[_], 2), &[3, 4] as &[_]),
+            ((&[10, 1, 10, 1, 10], 3), &[1, 3]),
+            ((&[10, 1, 10, 1, 10], 10), &[]),
+        ];
+
+        for ((height, threshold), expected) in test_cases {
+            assert_eq!(
+                test_utilities::unstable_sorted(S::stable_mountains(height.to_vec(), threshold)),
+                expected,
+            );
+        }
+    }
+}