題目描述

給定兩個整數n和k，將所有從1到n的整數分為兩類，第一類包含可以被k整除的整數（換句話說，這些整數是k的倍數）；

另一類包含其他整數。

您的任務是計算出每個類的平均值並以一行的方式輸出，數值之間以「 , 」作分隔，各數值精確至小數點後一位。

輸入格式

Two integers n and k

2 <= k <= 100

2 <= n <= 1000000

輸出格式

a float number with precision one decimal place

Samples

["100 16\r\n","10000 32","20 5"]

["56.0 , 50.1\r\n","5008.0 , 5000.3\r\n","12.5 , 10.0"]

提示

[Straight forward solution] You can simply use "loop and range()"to solve the problem.

[Advanced solution] However, naively using loop to classify and get the sum of the numbers may be too costly as the value of n can be up to 1,000,000. You could try to derive the math relationship behind the problem.

原始資料

• Zero1 題號：a098
• Hydro 題號：Z0098
• Locale：zh_TW
• Display：open