title: A* Graph search
body: <p><img src="https://i.stack.imgur.com/TGJKx.png" alt="http://i.imgur.com/ktdwhrT.png"></p>
  
  <p>Given the heuristic values h(A)=5, h(B)=1, using A* graph search, it will put A and B on the frontier with f(A)=2+5=7, f(B)=4+1=5, then select B for expansion, then put G on frontier with f(G)=4+4=8, then it will select A for expansion, but will not do anything since both S and B are already expanded and not on frontier, and therefore it will select G next and return a non-optimal solution.</p>
  
  <p>Is my argument correct?</p>