题解 | 计算一元二次方程

import sys

def format_number(num):
    """格式化数字，移除0值的负号"""
    # 考虑浮点数精度问题，接近0的数值视为0
    if abs(num) < 1e-9:
        return "0.00"
    # 格式化后如果是-0.00则替换为0.00
    return f"{num:.2f}".replace("-0.00", "0.00")

for line in sys.stdin:
    a, b, c = map(float, line.split(" "))
    if a == 0:
        print("Not quadratic equation")
    else:
        d = b ** 2 - 4 * a * c
        if d == 0:
            print(f"x1=x2={format_number((-b)/(2*a))}")
        elif d > 0:
            x1 = ((-b) + d ** 0.5) / (2 * a)
            x2 = ((-b) - d ** 0.5) / (2 * a)
            if x1 > x2:
                x1, x2 = x2, x1
            print(f"x1={format_number(x1)};x2={format_number(x2)}")
        else:
            s = -(b / (2 * a)) + 0.0001
            x = ((-d) ** 0.5) / (2 * abs(a))
            print(f"x1={format_number(s)}-{format_number(x)}i;" + f"x2={format_number(s)}+{format_number(x)}i")