erase draft implemented

Map.hpp

@@ -558,14 +558,52 @@ private:
   }
 
 public:
-  // TODO: erase via iterator
+  // TODO: check that the way of reconnecting next and prev works
   void erase(Iterator pos) {
     // simple cases
     Node *ref = pos.ref;
-
-    // 2 children just copy over the in order successor and remove successor
-
-    this->complex_erase(pos);
+    // 2 children
+    if (ref->left != nullptr && ref->right != nullptr) {
+      Node *next = ref->next;
+      Node *prev = ref->prev;
+      *ref = *next;
+      prev->next = next;
+      next->prev = prev;
+      this->erase(Iterator{next});
+    }
+    // single child which is left
+    else if (ref->left != nullptr && ref->right == nullptr) {
+      Node *next = ref->next;
+      Node *prev = ref->prev;
+      *ref = *ref->left;
+      prev->next = next;
+      next->prev = prev;
+    }
+    // single child which is right
+    else if (ref->left == nullptr && ref->right != nullptr) {
+      Node *next = ref->next;
+      Node *prev = ref->prev;
+      *ref = *ref->right;
+      prev->next = next;
+      next->prev = prev;
+    }
+    // no children and root
+    else if (ref->left == nullptr && ref->right == nullptr) {
+      this->root = nullptr;
+      this->nodes.erase(ref->value);
+    }
+    // no children and red
+    else if (ref->left == nodes.end() && ref->right == nodes.end()) {
+      Node *next = ref->next;
+      Node *prev = ref->prev;
+      prev->next = next;
+      next->prev = prev;
+      this->nodes.erase(ref->value);
+    }
+    // complicated case of black node with no kids
+    else {
+      this->complex_erase(pos);
+    }
   }
   void erase(const Key_T &key) { this->erase(this->find(key)); }
   void clear() {