一道简单的算法题

已知A，B坐标，且A为圆心，求圆与AB连线的交点坐标

import copy
class Point(object):
    def __init__(self,x=3,y=3):
        self.x = x
        self.y = y
A = Point(50,50) # 圆点
B = Point(3,3)

threshold = 0.01
target = copy.deepcopy(B)  # 初始点
dx = A.x - B.x
dy = A.y - B.y
dx_y = dx/dy
y_step = 0.01
x_step = y_step * dx_y
choice = None

import math

moves = {}
moves["up"] = [x_step,y_step]
moves["down"] = [-x_step,-y_step]

def cal_dist(p1,p2:Point)->float:
    return abs(math.sqrt((p1.x-p2.x) ** 2+(p1.y-p2.y)**2))

AB =  cal_dist(A,B)

# first_move = True

# choice = None
def move(target,choice):
    target.x +=moves[choice][0]
    target.y +=moves[choice][1]
    

import math
import copy

xs = []
ys = []

def find_point(r:int):
    """
    r:圆半径
    target： 目标点
    """
    start_loss = abs(math.sqrt((target.x-A.x) ** 2+(target.y-A.y)**2) - r) # 目标点到圆心的距离
    target.x +=moves["up"][0]
    target.y +=moves["up"][1]
    loss =abs(math.sqrt((target.x-A.x) ** 2+(target.y-A.y)**2) - r)
    if loss < start_loss:
        choice = "up"
    else:
        choice = "down"
    while loss > 0.01:
        move(target,choice)
        xs.append(target.x)
        ys.append(target.y)
        loss = abs(math.sqrt((target.x-A.x) ** 2+(target.y-A.y)**2) - r)
    return target

res = find_point(1)

res.x

49.289999999998784

res.y

49.289999999998784

xs

[3.0199999999999996,
 3.0299999999999994,
 3.039999999999999,
 3.049999999999999,
  ...
 13.009999999999787,
 ...]

import matplotlib.pyplot as plt
plt.plot(xs, ys)
plt.show()

output_9_0.png