2016 Update

Task/Permutation-test/C++/permutation-test-1.cpp

@@ -0,0 +1,39 @@
+#include<iostream>
+#include<vector>
+#include<numeric>
+#include<functional>
+
+class
+{
+public:
+    int64_t operator()(int n, int k){ return partial_factorial(n, k) / factorial(n - k);}
+private:
+    int64_t partial_factorial(int from, int to) { return from == to ? 1 : from * partial_factorial(from - 1, to); }
+    int64_t factorial(int n) { return n == 0 ? 1 : n * factorial(n - 1);}
+}combinations;
+
+int main()
+{
+    static constexpr int treatment = 9;
+    const std::vector<int> data{ 85, 88, 75, 66, 25, 29, 83, 39, 97,
+                                 68, 41, 10, 49, 16, 65, 32, 92, 28, 98 };
+
+    int treated = std::accumulate(data.begin(), data.begin() + treatment, 0);
+
+    std::function<int (int, int, int)> pick;
+    pick = [&](int n, int from, int accumulated)
+            {
+                if(n == 0)
+                    return accumulated > treated ? 1 : 0;
+                else
+                    return pick(n - 1, from - 1, accumulated + data[from - 1]) +
+                            (from > n ? pick(n, from - 1, accumulated) : 0);
+            };
+
+    int total   = combinations(data.size(), treatment);
+    int greater = pick(treatment, data.size(), 0);
+    int lesser  = total - greater;
+
+    std::cout << "<= : " << 100.0 * lesser  / total << "%  " << lesser  << std::endl
+              << " > : " << 100.0 * greater / total << "%  " << greater << std::endl;
+}

Task/Permutation-test/C++/permutation-test-2.cpp

@@ -0,0 +1,2 @@
+<= : 87.197168%  80551
+ > : 12.802832%  11827