Tight example for MST heuristic for metric TSP
<p>I'm looking for the tight example for MST heuristic which is and 2-approximation algorithm for metric Travelling Salesman Problem.</p>

<p>This algorithm can be found easily on the internet but I cannot find the tight example. By tight example I mean example in which given algorithm returns exactly 2 times worse solution than optimal.</p>

<p>Thanks.</p>