upd

contests/4contest/4.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+#include <iomanip>
+
+struct Acc {
+    double sum = 0;
+    size_t count = 0;
+
+    void operator()(double value) {
+        sum += value;
+        count++;
+    }
+};
+
+int main() {
+    std::vector<double> data;
+
+    double value;
+    while (std::cin >> value) data.push_back(value);
+
+    size_t n = data.size();
+    size_t first_cut = n / 10;
+
+    auto it_begin = data.begin() + first_cut;
+    auto it_end = data.end() - first_cut;
+
+    std::sort(it_begin, it_end);
+
+    size_t min_cut = (it_end - it_begin) / 10;
+
+    it_begin += min_cut;
+    it_end -= min_cut;
+
+    Acc acc = std::for_each(it_begin, it_end, Acc());
+
+    std::cout << std::fixed << std::setprecision(10);
+    std::cout << acc.sum / acc.count << std::endl;
+
+    return 0;
+}