Initial commit of code for dopelib, and ch 1, 2, and 12

libs/chapter2/remove_dups.cpp

@@ -0,0 +1,35 @@
+#include "chapter2.hpp"
+#include <unordered_map>
+
+/*
+Remove Dups!
+Write code to remove duplicates from an unsorted linked list.
+FOLLOW UP
+How would you solve this problem if a temporary buffer is not allowed?
+ */
+
+void remove_dups(DopeLinkedList* ll){
+  DopeNode* prev = ll->GetHead();
+  DopeNode* node = ll->GetHead();
+  DopeNode* tmp = NULL;
+  std::unordered_map<int, int> dup_tracker;
+  int iter_cnt = 0;
+
+  while(node->GetNext() != NULL){
+    if(dup_tracker.count(node->GetData())){
+      // remove node
+      prev->SetNext(node->GetNext());
+      tmp = node;
+      node = node->GetNext();
+      tmp->Reset();
+    } else {
+      dup_tracker[node->GetData()] += 1;
+      node = node->GetNext();
+      if (iter_cnt != 0){
+        prev = prev->GetNext();
+      }
+    }
+
+    iter_cnt++;
+  }
+}