To construct a Xorion with exactly $$$k$$$ peaks:

• Use the largest $$$k$$$ elements from $$$n$$$ down to $$$n-k+1$$$ to form the peaks.
• Place the smaller numbers between them to create valleys.

Peak Definition

An index $$$i$$$ is a peak if: - $$$a_i \gt a_{i-1} \quad \text{and} \quad a_i \gt a_{i+1}$$$

Construction Pattern

We can build the sequence as:

• $$$1, n, 2, n-1, 3, n-2, \dots, n-k+1, k+1, k+2, \dots, n-k$$$

  • $$$n, n-1, \dots, n-k+1$$$ → largest $$$k$$$ numbers → peaks
  • $$$1, 2, \dots, k$$$ → smaller numbers → valleys
  • Remaining numbers $$$(k+1, k+2, \dots, n-k)$$$ → fill the rest

Feasibility Condition

• For this construction to be valid:

  • $$$n - k + 1 \gt k + 1 \quad \implies \quad 2 \cdot k \lt n$$$

• If $$$2 \cdot k \ge n$$$, it is impossible to form exactly $$$k$$$ peaks → output -1.

Example

• Let $$$n = 7$$$, $$$k = 2$$$

  1. Largest 2 numbers for peaks: $$$7, 6$$$
  2. Smaller numbers for valleys: $$$1, 2$$$
  3. Remaining numbers: $$$3, 4, 5$$$

Construction:

• $$$1, 7, 2, 6, 3, 4, 5$$$

• Peaks at indices 2 and 4:

  • $$$a_2 = 7 \gt 1, 2$$$
  • $$$a_4 = 6 \gt 2, 3$$$

Summary

• Use largest numbers for peaks

• Interleave smaller numbers for valleys

• Check feasibility: $$$2 \cdot k \lt n$$$

• If not possible → output -1

test = int(input())
for _ in range(test):
    n, k = map(int, input().split())
    
    if 2 * k >= n:
        print(-1)
        continue
    
    ans = []
    left = 1          
    right = n         
    
    for i in range(k):
        ans.append(left)
        ans.append(right)
        left += 1
        right -= 1
    
    for num in range(left, right + 1):
        ans.append(num)
    
    print(*ans)