1 files changed, 59 insertions, 0 deletions
diff --git a/stats/three_gates.py b/stats/three_gates.py
new file mode 100644
index 0000000..4d6433a
--- /dev/null
+++ b/stats/three_gates.py
@@ -0,0 +1,59 @@
+import random
+
+import matplotlib.pyplot as plt
+
+gates = ['coat', 'coat', 'car']
+
+
+def not_change(N=1000):
+    win = 0
+    for i in range(N):
+        random.shuffle(gates)
+        # print(gates)
+        chosed = random.randint(0, 2)
+        print('chosed {}({})'.format(chosed, gates))
+        unchosed_coat = random.choice([i for i in range(3) if i != chosed and gates[i] != 'car'])
+        print('{} is a coat, change or not'.format(unchosed_coat))
+        final_chose = chosed
+        if gates[final_chose] == 'car':
+            win += 1
+            print('not change, win')
+        else:
+            print('not change, lose')
+    return win
+
+
+def change(N=1000):
+    win = 0
+    for i in range(N):
+        random.shuffle(gates)
+        # print(gates)
+        chosed = random.randint(0, 2)
+        print('chosed {}({})'.format(chosed, gates))
+        unchosed_coat = random.choice([i for i in range(3) if i != chosed and gates[i] != 'car'])
+        print('{} is a coat, change or not'.format(unchosed_coat))
+        for i in range(3):
+            if i != chosed and i != unchosed_coat:
+                final_chose = i
+        if gates[final_chose] == 'car':
+            print('change, win')
+            win += 1
+        else:
+            print('change, lose')
+    return win
+
+
+if __name__ == '__main__':
+    # N = 100000
+    # # print('not change, win {}/{}'.format(not_change(N), N))
+    # print('change, win {}/{}'.format(change(N), N))
+
+    not_change_rates = []
+    change_rates = []
+
+    for n in [10, 100, 1000, 10000, 100000, 100000]:
+        not_change_rates.append(not_change(n) / n)
+        change_rates.append(change(n) / n)
+
+    plt.plot(range(6), not_change_rates, range(6), change_rates)
+    plt.show()