CF1839A.The Good Array
普及/提高-
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题目描述
You are given two integers n and k .
An array a1,a2,…,an of length n , consisting of zeroes and ones is good if for all integers i from 1 to n both of the following conditions are satisfied:
- at least ⌈ki⌉ of the first i elements of a are equal to 1 ,
- at least ⌈ki⌉ of the last i elements of a are equal to 1 .
Here, ⌈ki⌉ denotes the result of division of i by k , rounded up. For example, ⌈36⌉=2 , ⌈511⌉=⌈2.2⌉=3 and ⌈47⌉=⌈1.75⌉=2 .
Find the minimum possible number of ones in a good array.
输入格式
Each test contains multiple test cases. The first line contains a single integer t ( 1≤t≤104 ) — the number of test cases.
The only line of each test case contains two integers n , k ( 2≤n≤100 , 1≤k≤n ) — the length of array and parameter k from the statement.
输出格式
For each test case output one integer — the minimum possible number of ones in a good array.
It can be shown that under the given constraints at least one good array always exists.
输入输出样例
输入#1
7 3 2 5 2 9 3 7 1 10 4 9 5 8 8
输出#1
2 3 4 7 4 3 2
说明/提示
In the first test case, n=3 and k=2 :
- Array [1,0,1] is good and the number of ones in it is 2 .
- Arrays [0,0,0] , [0,1,0] and [0,0,1] are not good since for i=1 the first condition from the statement is not satisfied.
- Array [1,0,0] is not good since for i=1 the second condition from the statement is not satisfied.
- All other arrays of length 3 contain at least 2 ones.
Thus, the answer is 2 .
In the second test case, n=5 and k=2 :
- Array [1,1,0,0,1] is not good since for i=3 the second condition is not satisfied.
- Array [1,0,1,0,1] is good and the number of ones in it is 3 .
- It can be shown that there is no good array with less than 3 ones, so the answer is 3 .
In the third test case, n=9 and k=3 :
- Array [1,0,1,0,0,0,1,0,1] is good and the number of ones in it is 4 .
- It can be shown that there is no good array with less than 4 ones, so the answer is 4 .
In the fourth test case, n=7 and k=1 . The only good array is [1,1,1,1,1,1,1] , so the answer is 7 .