aboutsummaryrefslogtreecommitdiff
path: root/soup_servings.py
diff options
context:
space:
mode:
Diffstat (limited to 'soup_servings.py')
-rw-r--r--soup_servings.py48
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))