帮我调试一个Python猜数字程序

Question

我正在尝试写一个Python程序，让程序来猜用户的数字。我觉得自己有点傻，卡在数学部分，感觉这就像是那种我已经努力了几个小时，但别人可能能轻松地从新角度看问题并解决它。我想先把用户的输入部分几乎完全去掉。以下是我目前的进展，程序在逻辑部分卡住了，最后只会不停地说猜的数字要么太低，要么太高，永远这样下去：

MIN=0
MAX=100
firstguess = MAX - MIN
firstguess = firstguess/2

while 1==1:
number = int(raw_input("Enter your number 0-100:"))
print firstguess
oldguess = firstguess
if firstguess > number:
    print "First guess is too high."
    raw_input()
    guess = int(25)
    print guess
    while guess != number:
        if guess > number:
            print "My guess was too high."
            raw_input()
            nextguess = oldguess - guess
            nextguess = nextguess/2
            nextguess = guess - nextguess
            oldguess = guess
            guess = nextguess
        elif guess == number:
            print "I win!"
            exit
        elif guess < number:
            print "My guess was too low."
            raw_input()
            nextguess = oldguess - guess
            nextguess = nextguess/2
            nextguess = nextguess + guess
            oldguess = guess
            guess = nextguess
elif firstguess == number:
    print "I win!"
elif firstguess < number:
    print "My first guess was too low."
    raw_input()
    guess = 75
    print guess
    print guess
    while guess != number:
        if guess > number:
            print "My guess was too high."
            raw_input()
            nextguess = oldguess - guess
            nextguess = nextguess/2
            nextguess = guess - nextguess
            oldguess = guess
            guess = nextguess
        elif guess == number:
            print "I win!"
            exit
        elif guess < number:
            print "My guess was too low."
            raw_input()
            nextguess = oldguess - guess
            nextguess = nextguess/2
            nextguess = nextguess + guess
            oldguess = guess
            guess = nextguess

Answer 1

好的，首先我不懂Python，其次我也不知道你的代码在干嘛，懒得去弄明白。为什么呢？因为我觉得你把事情搞得太复杂了。

我认为你可以用一个简单的二分查找来解决这个问题。用伪代码表示就是：

low = 0                        // lowest possible value of user's number
high = 100                     // highest possible value of user's number

while low < high
    guess = (low + high) / 2   // guess the average of low and hight
    if guess is too low        // if guess is too low
        then low = guess + 1   // then the lowest possible value is guess + 1
    if guess it too high       // if guess is too high
        then hight = guess - 1 // then the highest possible value is guess - 1
    if guess equals the value
        we've found the answer

at this point (low + high) / 2 should be the answer

这个算法会把搜索的范围一分为二，然后检查用户的数字在哪一边。举个例子，在范围 1-10 中，假设用户的数字是 3。这里 L 代表低值，H 代表高值，G 代表猜测：

L         G         H  | guess is too high so we set high to guess-1
0 1 2 3 4 5 6 7 8 9 10 |
                       |
L   G   H              | guess is too low so we set low to guess+1
0 1 2 3 4 5 6 7 8 9 10 |
                       |
      L H              | guess is in the same position as low and is correct so
0 1 2 3 4 5 6 7 8 9 10 | we've found the number

Answer 2

我可能在帮你做作业，但你看起来确实对这个问题做了认真尝试：

bounds = [0, 100]
minimum, maximum = bounds

number = int(raw_input('Pick a number [{0}-{1}]: '.format(minimum, maximum)))

while guess != number:
  guess = int((maximum + minimum) / 2)
  raw_input('Guessing {0}'.format(guess))

  if guess > number:
    maximum = guess
  elif guess < number:
    maximum = bounds[1]
    minimum = guess

print 'I win!'

这个逻辑很简单：

1. 先设定一个猜测的范围，包括最小值和最大值。
2. 让用户选择一个数字，存储为 number。
3. 只要猜测的数字不等于用户选择的数字，就一直重复以下步骤：
   1. 找出最小值和最大值之间的中间值。
   2. 如果猜测的数字比用户选择的数字大，那说明用户选择的数字一定比这个猜测小，所以我们把最大猜测值设为当前的猜测值。
   3. 如果猜测的数字比用户选择的数字小，那我们就把最大值设为可能的最大数字，把最小值设为当前的猜测值。
4. 一旦猜测的数字等于用户选择的数字，循环就结束，我们就赢了。