我是新的python，我将非常感谢，如果有人能帮我找到我的代码中的错误。谢谢你提前。
这个问题要求我们找到一个最佳储蓄率，以在36个月内支付一套房子的首付款。由于准确地达到这个目标是一个挑战，答案只需要在所需首付款的100美元以内。
为了简化问题，假设：
1.你的半年加薪是0.07（7%）
1.您的投资年回报率为0.04（4%）
1.首付款是房价的0.25（25
1.你存钱买房子的费用是100万美元。
下面是我的原始代码：

annual_salary=float(input("Enter your annual salary:"))
semi_annual_raise=0.07
total_cost=1000000
portion_down_payment = 0.25
current_saving=0
r=0.04
low=0
high=10000
guess=(low+high)/2
numGuesses=0
while abs(portion_down_payment*total_cost-current_saving)>=100:
    current_saving=0
    portion_saved=guess/10000
    for i in range (36):
        current_saving+=current_saving*r/12+annual_salary/12*portion_saved
        if i%6==0 and i>0:
            annual_salary+=annual_salary*semi_annual_raise
    
    if portion_down_payment*total_cost-current_saving>0:
        low=guess
    else:
        high=guess
    guess=(low+high)/2
    numGuesses+=1   
    if numGuesses > 1000:
        break
if numGuesses>1000:
    print("It is not possible to pay the down payment in three years.")
else:
    rate=guess/10000
    print("steps in bisection search is",numGuesses,"and the best saving rate is",rate)

当输入150000作为annual_salary时，结果为：

It is not possible to pay the down payment in three years.

因为它不会返回正确的答案，我使用了一个函数来计算curring节省，代码如下所示：

annual_salary=float(input("Enter your annual salary:"))
semi_annual_raise=0.07
total_cost=1000000
portion_down_payment = 0.25
r=0.04
low=0
high=10000
guess=(low+high)/2
numGuesses=0
def current_saving(annual_salary,guess,months):
    portion_saved=guess/10000
    saving=0
    r=0.04
    semi_annual_raise=0.07
    for i in range (months):
        saving+=saving*r/12+annual_salary/12*portion_saved
        if i%6==0 and i>0:
            annual_salary+=annual_salary*semi_annual_raise
    return(saving)
total=0
while abs(portion_down_payment*total_cost-total)>=100:
    total=current_saving(annual_salary,guess,36)
    if portion_down_payment*total_cost-total>0:
        low=guess
    else:
        high=guess
    guess=(low+high)/2
    numGuesses+=1   
    if numGuesses > 1000:
        break
if numGuesses>1000:
    print("It is not possible to pay the down payment in three years.")
else:
    rate=guess/10000
    print("steps in bisection search is",numGuesses,"and the best saving rate is",rate)

当这次输入150000作为annual_salary时，结果是：

steps in bisection search is 7 and the best saving rate is 0.44140625

我觉得这两个版本基本上做同样的事情，为什么第一个不能工作，但第二个可以呢？我假设while循环中有什么错误，但我不能确定我的错误。再次感谢您的帮助！