백준 #2022 - 사다리 (python3)

import math

x,y,c = map(float, input().split(' '))
d = 1.0
high = min(x,y)
low = 0.0

while (low+0.001) <= high:
    d = (high+low)/2.0
    e = math.sqrt((x**2)-(d**2))
    f = math.sqrt((y**2)-(d**2))
    if c == round((f*e)/(f+e),4):
        break
    elif c > (f*e)/(f+e):
        high = d
    elif c < (f*e)/(f+e):
        low = d
print('%.03f'%d)