From 6f68e1818229e0d2dad760062e6b5bb137b88f5b Mon Sep 17 00:00:00 2001
From: zhang <zch921005@126.com>
Date: Sun, 23 Jan 2022 12:42:38 +0800
Subject: =?UTF-8?q?=E9=9A=8F=E6=9C=BA=E6=B8=B8=E8=B5=B0=20&=20ortools=20de?=
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---
 prob/random_walk_demo.py | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 prob/random_walk_demo.py

(limited to 'prob/random_walk_demo.py')

diff --git a/prob/random_walk_demo.py b/prob/random_walk_demo.py
new file mode 100644
index 0000000..6212528
--- /dev/null
+++ b/prob/random_walk_demo.py
@@ -0,0 +1,48 @@
+
+import random
+
+
+def random_walk(N):
+    x, y = 0, 0
+    choices = ['N', 'S', 'E', 'W']
+    for i in range(N):
+        step = random.choice(choices)
+        if step == 'N':
+            y += 1
+        elif step == 'S':
+            y -= 1
+        elif step == 'E':
+            x += 1
+        else:
+            x -= 1
+    return x, y
+
+
+def random_walk_2(N):
+    x, y = 0, 0
+    for i in range(N):
+        dx, dy = random.choice([[0, 1], [0, -1], [1, 0], [-1, 0]])
+        x += dx
+        y += dy
+    return x, y
+
+
+def distance_from_home(x, y):
+    return abs(x) + abs(y)
+
+
+if __name__ == '__main__':
+    # for i in range(25):
+    #     x, y = random_walk_2(10)
+    #     print(f'x = {x}, y = {y}, distance from home: {distance_from_home(x, y)}')
+
+    number_of_walks = 50000
+    for walk_length in range(1, 31):
+        no_transport = 0
+        for i in range(number_of_walks):
+            x, y = random_walk(walk_length)
+            dist = distance_from_home(x, y)
+            if dist <= 5:
+                no_transport += 1
+        no_transport_percentage = float(no_transport)/number_of_walks
+        print(f'walk_length: {walk_length}, no_transport_percentage: {no_transport_percentage}')
-- 
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