This is a nice observation. I remember being given change-making assignments in school, and being unable to complete them because I was not sure that the greed

This is a nice observation. I remember being given change-making assignments in school, and being unable to complete them because I was not sure that the greedy algorithm (http://en.wikipedia.org/wiki/Change-making_problem#Greedy_method http://en.wikipedia.org/wiki/Change-making_problem#Greedy_me...) would always give the optimal result. I was not able to articulate the reason for my uneasiness until years after I had failed to complete the work.