Created
September 27, 2014 21:27
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| class Replier: | |
| def __init__(self, secret): | |
| self._diff = None | |
| self._secret = secret | |
| def answer(self, val): | |
| last_diff = self._diff | |
| self._diff = abs(val - self._secret) | |
| return (-1 if last_diff and self._diff > last_diff else 1) if \ | |
| self._diff else 0 | |
| def find2(rep, N): | |
| """Find the secret in ~ 2 lg N guesses.""" | |
| lo = 1 | |
| hi = N | |
| while lo < hi: | |
| if not rep.answer(lo): | |
| return lo | |
| ans = rep.answer(hi) | |
| if not ans: | |
| return hi | |
| mid = (lo + hi) / 2 | |
| if ans > 0: | |
| lo = mid | |
| else: | |
| hi = mid | |
| return lo | |
| def find(rep, N): | |
| """Find the secret in ~ lg N guesses.""" | |
| lo = 1 | |
| hi = N | |
| guess = 1 | |
| decision_pt = hi | |
| if not rep.answer(1): | |
| return lo | |
| while hi - lo > 1: | |
| guess = lo + hi - guess | |
| ans = rep.answer(guess) | |
| if not ans: | |
| return ans | |
| mid = (lo + hi) / 2 | |
| if decision_pt == lo: | |
| if ans > 0: | |
| hi = mid | |
| else: | |
| lo = mid | |
| decision_pt = hi | |
| else: | |
| if ans > 0: | |
| lo = mid | |
| else: | |
| hi = mid | |
| decision_pt = lo | |
| return hi if rep.answer(lo) else lo |
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