Fix lambda example to match the generator behavior of the solution

code/lambdas/randomize.cpp

@@ -10,7 +10,7 @@ using namespace std;
 template<class T>
 struct Generator {
     T m_value, m_step;
-    Generator(T initial, T step):m_value(initial-step), m_step(step){};
+    Generator(T initial, T step):m_value(initial), m_step(step){};
     T operator()() {
         T cur_value = m_value;
         m_value += m_step;