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

libs/chapter1/is_unique.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include "chapter1.hpp"
+
+/* Prompt
+   Is Unique: Implement an algorithm to determine if a string
+   has all unique characters. What if you cannot use additional data
+   structures?
+*/
+
+bool IsUnique(const char* s, int len){
+  int tracker[255]= {};
+
+  for(int i=0; i<len; ++i){
+    int tracker_index = static_cast<int>(s[i]);
+    tracker[tracker_index] += 1;
+    if (tracker[tracker_index] > 1){
+      return false;
+    }
+  }
+  return true;
+}