On Sun, 14 Dec 2008 21:42:33 +0000, Lie Ryan wrote: > I'm sure someday, there will be a student who comes to class late and > sees this on the board: "Design a comparison sorting algorithm that has > better than O(n * log n) lower bound complexity." The unsuspecting > student copied it, thinking it's a homework. He crunched to the problem, > going to various meditations and yoga classes before finding a way that > works just before deadline, handing out the work a bit late. Six weeks > later, his professor called and said: "You know what you just did? > You've just found a problem that was supposed to be an example of > unsolvable problem." > > It has happened before, why not again? > http://www.snopes.com/college/homework/unsolvable.asp
Because as you described it, it *hasn't* happened before. There is the world of difference between an unsolvABLE problem and one that is unsolvED. All the positive thinking in the world won't help you: * make a four-sided triangle; * write down a completely accurate rational expansion for pi or the square-root of 2; * split a magnet into two individual poles; * find an integer solution to 3*n = 7; * solve the Halting Problem; * fit n items into n-1 pigeonholes without putting two items in the one pigeonhole; * create a compression algorithm that will compress random data; * or design a comparison sort which does fewer than O(n*log n) two-way comparisons in the worst case, or fewer than O(n) comparisons in the best case. Some things really don't have a solution, no matter how much power of positive thinking you apply to it. -- Steven -- http://mail.python.org/mailman/listinfo/python-list