Python中的立方根

用Python实现求立方根

n = float(input())
if n == 0:
    print(0)
if n > 0:
    sig = 1
else:
    sig = -1
n = abs(n)

if n > 1:
    start = 0
    end = n
else:
    start = n
    end = 1
mid = (start + end) / 2
while abs(mid ** 3 - n) > 0.001:
    if mid ** 3 > n:
        end = mid
    else:
        start = mid
    mid = (start + end) / 2
print(round(sig * mid, 1))