4kyu(cpp): add „Memoized Log Cutting“

Signed-off-by: Matej Focko <mfocko@redhat.com>

4kyu/memoized_log_cutting/solution.cpp

@@ -0,0 +1,68 @@
+#include <map>
+#include <vector>
+
+// Your new function as given to you by me, your boss.
+int cut_log(const std::vector<int>& p, int n)
+{
+    std::map<int, int> cache;
+
+    // Some array to store calculated values
+    for (int j = 1; j <= n; j++) {
+        cache[j] = (j < static_cast<int>(p.size())) ? p[j] : 0;
+
+        for (int i = 1; i < j; i++) { // Two nested loops = Θ(n^2)
+            cache[j] = std::max(cache[j], cache[i] + cache[j - i]);
+        }
+    }
+
+    return cache[n];
+}
+
+#pragma region tests
+
+#include <gtest/gtest.h>
+
+static const std::vector<int>& p()
+{
+    static std::vector<int> _p({ 0, 1, 5, 8, 9, 10, 17, 17, 20, 24,
+        30, 32, 35, 39, 43, 43, 45, 49, 50, 54,
+        57, 60, 65, 68, 70, 74, 80, 81, 84, 85,
+        87, 91, 95, 99, 101, 104, 107, 112, 115, 116,
+        119, 121, 125, 129, 131, 134, 135, 140, 143, 145,
+        151 });
+
+    return _p;
+}
+
+TEST(sample, one)
+{
+    ASSERT_EQ(cut_log(p(), 1), 1);
+}
+
+TEST(sample, five)
+{
+    ASSERT_EQ(cut_log(p(), 5), 13);
+}
+
+TEST(sample, eight)
+{
+    ASSERT_EQ(cut_log(p(), 8), 22);
+}
+
+TEST(sample, ten)
+{
+    ASSERT_EQ(cut_log(p(), 10), 30);
+}
+
+TEST(sample, twenty_two)
+{
+    ASSERT_EQ(cut_log(p(), 22), 65);
+}
+
+int main(int argc, char** argv)
+{
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
+
+#pragma endregion /* tests */

README.md

@@ -41,6 +41,7 @@
 - [Infix to Postfix Converter](https://www.codewars.com/kata/52e864d1ffb6ac25db00017f) - [solution](4kyu/infix_to_postfix_converter)
 - [Range Extraction](https://www.codewars.com/kata/51ba717bb08c1cd60f00002f) - [solution](4kyu/range_extraction)
 - [Shortest Knight Path](https://www.codewars.com/kata/549ee8b47111a81214000941) - [solution](4kyu/shortest_knight_path)
+- [Memoized Log Cutting](https://www.codewars.com/kata/54b058ce56f22dc6fe0011df) - [solution](4kyu/memoized_log_cutting)
 
 ### JS