Create mean-of-array-after-removing-some-elements.cpp

Author: kamyu104

C++/mean-of-array-after-removing-some-elements.cpp

@@ -0,0 +1,13 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    double trimMean(vector<int>& arr) {
+        static const int P = 20;
+        const int k = size(arr) / P;
+        nth_element(begin(arr), begin(arr) + k - 1, end(arr));
+        nth_element(begin(arr) + k, end(arr) - k, end(arr));
+        return accumulate(begin(arr) + k, end(arr) - k, 0.0) / (size(arr) - 2 * k);
+    }
+};