|
|
back to boardWhat does it mean?(Что это означает) I don't understand!!! How given (2, aa) answer is 6. I think that must be 4!!! Please help, who know that!!!!! (Я не понел Как 2 и аа могут дать ответ 6 Я думаю что должно быть 4 Помогите------------) Re: What does it mean?(Что это означает) Posted by lxn 22 Jan 2018 15:37 expected time is inifinite sum of time * p(time), where p(time) is the probability to get resulting string exactly in 'time' steps. for aa: probability to get 'aa' in exactly 1 step is 0. (simple) probability to get 'aa' in exactly 2 steps is 1/4 (simple) probability to get 'aa' in exactly n steps is probability to get a string of length == n - 1 that ends with 'a', and doesn't contain 'aa' as substring multiplyed by 1/2 (when you have such string there is a 1/2 chance that the next character will be 'a'). for n == 3: 1/8, for n == 4: 1/8 etc. If you simulate such steps and get a sum for n = [2.. 10000] you will get answer equal to 6 PS. this is simulation of 10 steps: 0.000000 * 1 0.250000 * 2 0.125000 * 3 0.125000 * 4 0.093750 * 5 0.078125 * 6 0.062500 * 7 0.050781 * 8 0.041016 * 9 0.033203 * 10 |
|
|