Data update

Task/100-prisoners/YAMLScript/100-prisoners.ys

@@ -0,0 +1,79 @@
+!yamlscript/v0
+
+defn main(n=5000):
+  :: https://rosettacode.org/wiki/100_prisoners
+
+  random-successes optimal-successes run-count =:
+    simulate-n-runs(n)
+      .slice(q(random-successes optimal-successes run-count))
+
+  say: "Probability of survival with random search: $F(random-successes / run-count)"
+
+  say: "Probability of survival with ordered search: $F(optimal-successes / run-count)"
+
+defn simulate-n-runs(n):
+  :: Simulate n runs of the 100 prisoner problem and returns a success count
+     for each search method.
+
+  loop random-successes 0, optimal-successes 0, run-count 0:
+    # If we've done the loop n times
+    if n == run-count:
+      # return results
+      then::
+        random-successes  :: random-successes
+        optimal-successes :: optimal-successes
+        run-count         :: run-count
+
+      # Otherwise, run for another batch of prisoners
+      else:
+        next-result =: simulate-100-prisoners()
+        recur:
+          (random-successes + next-result.random)
+          (optimal-successes + next-result.optimal)
+          run-count.++
+
+defn simulate-100-prisoners():
+  :: Simulates all prisoners searching the same drawers by both strategies,
+     returns map showing whether each was successful.
+
+  # Create 100 drawers with randomly ordered prisoner numbers:
+  drawers =: random-drawers()
+  hash-map:
+    :random   try-luck(drawers search-50-random-drawers)
+    :optimal  try-luck(drawers search-50-optimal-drawers)
+
+defn try-luck(drawers drawer-searching-function):
+  :: Returns 1 if all prisoners find their number otherwise 0.
+
+  loop prisoners range(100):
+    if prisoners.?:
+      if prisoners.0.drawer-searching-function(drawers):
+        recur: rest(prisoners)
+        else: 0
+      else: 1
+
+defn search-50-optimal-drawers(prisoner-number drawers):
+  :: Open 50 drawers according to the agreed strategy, returning true if
+     prisoner's number was found.
+
+  loop next-drawer prisoner-number, drawers-opened 0:
+    when drawers-opened != 50:
+      result =: drawers.$next-drawer
+      result == prisoner-number ||:
+        recur: result drawers-opened.++
+
+defn search-50-random-drawers(prisoner-number drawers):
+  :: Select 50 random drawers and return true if the prisoner's number was
+     found.
+
+  drawers:
+    .shuffle()
+    .take(50)
+    .filter(eq(prisoner-number))
+    .count()
+    .eq(1)
+
+defn random-drawers():
+  :: Returns a list of shuffled numbers.
+
+  shuffle: range(100)