题目描述
An array is said to be good if all its elements are distinct, i.e. no two elements of the array are equal to each other.
You are given a positive integer N and an integer K such that N ≤ K ≤ $\binom{N+1}{2}$.
Construct an array A of length N that satisfies the following conditions
A has exactly K good (contiguous) subarrays, and
Every element of A is an integer from 1 to N (both inclusive).
If there are multiple such arrays, you can print any of them.
Note: It can be shown that for all inputs satisfying the given constraints, there is always a valid solution.
------ Input Format ------
- The first line contains an integer T, the number of testcases. The description of the T testcases follow.
- Each testcase consists of a single line with two space separated integers, N and K respectively.
------ Output Format ------
- For each testcase print N space separated integers, the elements of the constructed array.
- If there are multiple outputs, you can print any of them.
- Your output will be considered correct only if the following conditions are satisfied,
- Every element of the array is between 1 and N, and
- The array has exactly K good subarrays
------ Constraints ------
$1 ≤ T ≤ 10^{5}$
$1 ≤ N ≤ 10^{5}$
$N ≤ K ≤ \binom{N+1}{2}$
- Sum of $N$ over all testcases is atmost $3 \cdot 10^{5}$.
----- Sample Input 1 ------
3
5 5
5 15
5 7
----- Sample Output 1 ------
1 1 1 1 1
1 2 3 4 5
1 2 2 1 1
----- explanation 1 ------
Test Case 1: $N = 5, K = 5$. All subarrays of length $1$ are good, therefore every array of size $N$ has at least $N$ good subarrays. If all elements are equal then these will be the only good subarrays so the given array $\{1, 1, 1, 1, 1\}$ is a valid solution. Observe that under the constraints there are $5$ different solutions (one for each value $1$ through $5$) and all of them will be considered correct.
Test Case 2: $N = 5, K = 15$. There are only $\binom{N + 1}{2} = 15$ subarrays, including the array itself. Therefore the array itself must be good which leads us to the solution given above. Any permutation of $\{1, 2, 3, 4, 5\}$ is also a valid solution, thus there are $5! = 120$ different solutions to this case and all of them will be considered correct.
Test Case 3: $N = 5, K = 7$. The constructed array is $A = \{1, 2, 2, 1, 1\}$. You may verify that the only good subarrays of $A$, in addition to the $5$ subarrays of length $1$, are those shown below (subarrays are highlighted red).
- $\{{\color{red}1}, {\color{red}2}, 2, 1, 1\}$
- $\{1, 2, {\color{red}2}, {\color{red}1}, 1\}$
输入格式
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输出格式
见题面