Leetcode 808. Soup Servings

Compute the probability that soup A is emptied before B (counting ties as half) under a random process of four equal-probability pours that reduce A and B by {100,0}, {75,25}, {50,50}, {25,75} mL until one or both hit zero. Solve it as a recursive/DP probability on the remaining volumes (commonly discretized in 25 mL units) with memoization and base cases for A<=0 or B<=0 (with an optimization that for large n the answer approaches 1).