Data commit

Task/100-prisoners/D/100-prisoners.d

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+import std.array;
+import std.random;
+import std.range;
+import std.stdio;
+import std.traits;
+
+bool playOptimal() {
+    auto secrets = iota(100).array.randomShuffle();
+
+    prisoner:
+    foreach (p; 0..100) {
+        auto choice = p;
+        foreach (_; 0..50) {
+            if (secrets[choice] == p) continue prisoner;
+            choice = secrets[choice];
+        }
+        return false;
+    }
+
+    return true;
+}
+
+bool playRandom() {
+    auto secrets = iota(100).array.randomShuffle();
+
+    prisoner:
+    foreach (p; 0..100) {
+        auto choices = iota(100).array.randomShuffle();
+        foreach (i; 0..50) {
+            if (choices[i] == p) continue prisoner;
+        }
+        return false;
+    }
+
+    return true;
+}
+
+double exec(const size_t n, bool function() play) {
+    size_t success = 0;
+    for (int i = n; i > 0; i--) {
+        if (play()) {
+            success++;
+        }
+    }
+    return 100.0 * success / n;
+}
+
+void main() {
+    enum N = 1_000_000;
+    writeln("# of executions: ", N);
+    writefln("Optimal play success rate: %11.8f%%", exec(N, &playOptimal));
+    writefln(" Random play success rate: %11.8f%%", exec(N, &playRandom));
+}