1619. Mean of Array After Removing Some Elements: AC

Author: tan-wei

src/solution/mod.rs

@@ -1220,3 +1220,4 @@ mod s1614_maximum_nesting_depth_of_the_parentheses;
 mod s1615_maximal_network_rank;
 mod s1616_split_two_strings_to_make_palindrome;
 mod s1617_count_subtrees_with_max_distance_between_cities;
+mod s1619_mean_of_array_after_removing_some_elements;

src/solution/s1619_mean_of_array_after_removing_some_elements.rs

@@ -0,0 +1,85 @@
+/**
+ * [1619] Mean of Array After Removing Some Elements
+ *
+ * Given an integer array arr, return the mean of the remaining integers after removing the smallest 5% and the largest 5% of the elements.
+ * Answers within 10^-5 of the actual answer will be considered accepted.
+ *  
+ * Example 1:
+ *
+ * Input: arr = [1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3]
+ * Output: 2.00000
+ * Explanation: After erasing the minimum and the maximum values of this array, all elements are equal to 2, so the mean is 2.
+ *
+ * Example 2:
+ *
+ * Input: arr = [6,2,7,5,1,2,0,3,10,2,5,0,5,5,0,8,7,6,8,0]
+ * Output: 4.00000
+ *
+ * Example 3:
+ *
+ * Input: arr = [6,0,7,0,7,5,7,8,3,4,0,7,8,1,6,8,1,1,2,4,8,1,9,5,4,3,8,5,10,8,6,6,1,0,6,10,8,2,3,4]
+ * Output: 4.77778
+ *
+ *  
+ * Constraints:
+ *
+ * 	20 <= arr.length <= 1000
+ * 	arr.length is a multiple of 20.
+ * 	<font face="monospace">0 <= arr[i] <= 10^5</font>
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/mean-of-array-after-removing-some-elements/
+// discuss: https://leetcode.com/problems/mean-of-array-after-removing-some-elements/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn trim_mean(arr: Vec<i32>) -> f64 {
+        let mut arr = arr;
+
+        arr.sort_unstable();
+
+        let cut = arr.len() / 20;
+
+        arr[cut..arr.len() - cut].iter().sum::<i32>() as f64 / (arr.len() - 2 * cut) as f64
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1619_example_1() {
+        let arr = vec![1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3];
+
+        let result = 2.00000;
+
+        assert_f64_near!(Solution::trim_mean(arr), result);
+    }
+
+    #[test]
+    fn test_1619_example_2() {
+        let arr = vec![6, 2, 7, 5, 1, 2, 0, 3, 10, 2, 5, 0, 5, 5, 0, 8, 7, 6, 8, 0];
+
+        let result = 4.00000;
+
+        assert_f64_near!(Solution::trim_mean(arr), result);
+    }
+
+    #[test]
+    fn test_1619_example_3() {
+        let arr = vec![
+            6, 0, 7, 0, 7, 5, 7, 8, 3, 4, 0, 7, 8, 1, 6, 8, 1, 1, 2, 4, 8, 1, 9, 5, 4, 3, 8, 5, 10,
+            8, 6, 6, 1, 0, 6, 10, 8, 2, 3, 4,
+        ];
+
+        let result = 4.777777777777778;
+
+        assert_f64_near!(Solution::trim_mean(arr), result);
+    }
+}