restructuring

src/datastructures/smart_map.cpp

@@ -0,0 +1,80 @@
+#include <unordered_map>
+#include <vector>
+#include <string>
+#include <optional>
+#include <chrono>
+#include <algorithm>
+#include <bits/stdc++.h>
+
+constexpr int benchmark_loops = 1000000;
+
+template <typename KeyType, typename ValueType>
+class smart_map {
+  private:
+    bool use_hmap = false;
+    std::unordered_map<KeyType, ValueType> hmap;
+
+    double assess_hmap(const std::vector<std::pair<KeyType, ValueType>> check) {
+      const auto& start = std::chrono::high_resolution_clock::now();
+      for(int i = 0; i < benchmark_loops; i++) {
+        for(const auto& check_item : check) {
+          assert(check_item.second == hmap[check_item.first]);
+        }
+      }
+      const auto& end = std::chrono::high_resolution_clock::now();
+      auto duration = std::chrono::duration<double, std::nano>(end - start).count();
+      return duration;
+    }
+
+    double assess_vmap(const std::vector<std::pair<KeyType, ValueType>> check) {
+      const auto& start = std::chrono::high_resolution_clock::now();
+      for(int i = 0; i < benchmark_loops; i++) {
+        for(const auto& check_item : check) {
+          for(const auto& item : hmap) {
+            if(check_item.first == item.first) {
+              assert(check_item.second == item.second);
+            }
+          }
+        }
+      }
+      const auto& end = std::chrono::high_resolution_clock::now();
+      auto duration = std::chrono::duration<double, std::nano>(end - start).count();
+      return duration;
+    }
+
+  public:
+    smart_map () = default; 
+
+    void assess_datastructure() {
+      std::vector<std::pair<KeyType, ValueType>> vals(hmap.begin(), hmap.end());
+      std::shuffle(vals.begin(), vals.end(), std::default_random_engine(570));
+      use_hmap = assess_hmap(vals) > assess_vmap(vals);
+    }
+
+    bool will_use_hmap() {
+      return use_hmap;
+    }
+
+    ValueType* get(const KeyType& key) {
+      if(use_hmap) {
+        if(hmap.find(key) != hmap.end()) {
+          return &hmap[key];
+        } else {
+          return NULL;
+        }
+      }
+
+      for(auto& item : hmap) {
+        if(item.first == key) {
+          std::string& ref = item.second;
+          return &ref;
+        }
+      }
+      
+      return NULL; 
+    }
+
+    void insert(const KeyType key, const ValueType value) {
+      hmap[key] = value;
+    }
+};