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ericzhang-cn/coursera-prob-w5p10.py

Last active December 24, 2015 06:59
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  1. ericzhang-cn renamed this gist Sep 30, 2013. 1 changed file with 0 additions and 0 deletions.
    0 coursera-prob-w5p10 → coursera-prob-w5p10.py
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  2. ericzhang-cn revised this gist Sep 30, 2013. No changes.
  3. ericzhang-cn created this gist Sep 30, 2013.
    30 changes: 30 additions & 0 deletions coursera-prob-w5p10
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    # -*- coding: utf-8 -*-

    from math import *
    from random import *

    ### 一次测试 ###
    def test():
    speed = 4.0 #初速度
    distance = 0 #已经走过的距离
    threshold = log(50) / 100 #每秒中枪的概率

    while distance < 400:
    distance += speed #以当前速度移动

    if random() < threshold: #如果中枪，则判断是否死亡，如果不死亡，速度减半
    if speed == 0.5:
    return 0 #死亡！
    else:
    speed /= 2

    return 1 #成功通过！

    ### 模拟 ###
    succ = 0.0 #成功次数
    times = 100000 #模拟次数，可随需要更改，越大则越准确，但耗时越多
    for i in range(0, times):
    if test() == 1:
    succ += 1

    print round(succ / times, 2) #成功频率，以此作为概率估算值，结果保留两位小数