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Diffstat (limited to 'soup_servings.py')
-rw-r--r-- | soup_servings.py | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/soup_servings.py b/soup_servings.py new file mode 100644 index 0000000..15d7eaf --- /dev/null +++ b/soup_servings.py @@ -0,0 +1,48 @@ +# 808. Soup Servings + +""" +there are two ops of soup: op a, and op b. initially, we have 'n' ml of +each op of soup. there are four kinds of operations: +1. serve 100 ml of soup a and 0ml of soup b +2. serve 75ml of soup a and 25ml of soup b +3. serve 50ml of soup a and 50ml of soup b +4. serve 25ml of soup a and 75ml of soup b +when we serve some soup, we give it to someone, and we no longer have it. +each turn, we will choose from the four operations with an equal probability +of '0.25'. if the remaining volume of soup is not enough to complete the +operation, we will serve as much as possible. we stop once we no longer have +some quantity of both ops of soup. note that we do not have an operation +where all 100 ml's of soup b are used first. return the probability that soup +a will be empty first, plus half the probability that a and b become empty at +the same time. answers within '10^-5' of the actual answer will be accepted. +""" + + +class Solution(object): + def probability(self, a, b): + if a <= 0 and b > 0: + return 1 + if a <= 0 and b <= 0: + return 0.5 + if b <= 0 and a > 0: + return 0 + op1 = self.probability(a - 100, b) + op2 = self.probability(a - 75, b - 25) + op3 = self.probability(a - 50, b - 50) + op4 = self.probability(a - 25, b - 75) + return 0.25 * (op1 + op2 + op3 + op4) + + def soupServings(self, n): + """ + :type n: int + :rtype: float + """ + if n > 5000: + return 1.0 + return self.probability(n, n) + + +if __name__ == "__main__": + obj = Solution() + print(obj.soupServings(50)) + print(obj.soupServings(100)) |