keep笔试
keep的最小二乘调了1个多小时还是AC为0。emmmmm。求大佬回帖
题目分别是差值中位数、密码校验、最小二乘。AC：90%，100%，0%😥
import sys
X = []
Y = []
for line in sys.stdin:
x, y = list(map(int, line.split(" ")))
X.append(x)
Y.append(y)
s1 = s2 = s3 = s4 = 0
n = len(X)
for i in range(n):
s1 = s1 + X[i] * Y[i]
s2 = s2 + X[i]
s3 = s3 + Y[i]
s4 = s4 + X[i] * X[i]
b = (s2 * s3 - n * s1) / (s2 *s2-s4*n)
a = (s3 - b * s2) / n
print(str(b), str(a), sep="\t")
def get_two_float(f_str, n):
f_str = str(f_str) # f_str = '{}'.format(f_str) 也可以转换为字符串
a, b, c = f_str.partition('.')
c = (c+"0"*n)[:n] # 如论传入的函数有几位小数，在字符串后面都添加n为小数0
return ".".join([a, c]) 
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