fix(post): fetch code lazily

public/code/algorithms/extrema-circular-buffer/map.cpp

@@ -0,0 +1,56 @@
+#include <deque>
+#include <map>
+#include <stdexcept>
+
+class ExtremaCircularBuffer {
+public:
+  ExtremaCircularBuffer(size_t capacity) : capacity(capacity) {}
+
+  void push_back(double value) {
+    if (prices.size() == capacity) {
+      double front = prices.front();
+
+      if (--sorted_prices[front] == 0)
+        sorted_prices.erase(front);
+      prices.pop_front();
+    }
+
+    prices.push_back(value);
+    ++sorted_prices[value];
+  }
+
+  void pop_front() {
+    if (prices.empty()) {
+      throw std::out_of_range("Cannot pop_front() from empty buffer");
+    }
+
+    double front = prices.front();
+
+    if (--sorted_prices[front] == 0)
+      sorted_prices.erase(front);
+    prices.pop_front();
+  }
+
+  size_t size() const { return prices.size(); }
+
+  double get_max() const {
+    if (prices.empty()) {
+      throw std::out_of_range("Cannot find max() of empty buffer");
+    }
+
+    return sorted_prices.rbegin()->first;
+  }
+
+  double get_min() const {
+    if (prices.empty()) {
+      throw std::out_of_range("Cannot find min() of empty buffer");
+    }
+
+    return sorted_prices.begin()->first;
+  }
+
+private:
+  std::deque<double> prices;
+  std::map<double, size_t> sorted_prices;
+  size_t capacity;
+};