# GMGM - Editorial

Author: pols_agyi_pols
Testers: kingmessi
Editorialist: iceknight1093

TBD

None

# PROBLEM:

You have two guns: one that can shoot targets at a distance \leq D, and one that can shoot targets at a distance \gt D.
You’re initially holding the short-range gun. How many times will you need to change guns to shoot N targets in order, with the i-th being at a distance of A_i from you?

# EXPLANATION:

Observe that you only need to change guns when you need to shoot a target that’s \gt D distance away immediately after shooting one that \leq D distance; or vice versa.

So, the number of changes required is just the number of indices i such that:

• A_i \leq D and A_{i-1} \gt D; or
• A_i \gt D and A_{i-1} \leq D.

This can be counted using a simple loop.

# TIME COMPLEXITY:

\mathcal{O}(N) per testcase.

# CODE:

Editorialist's code (Python)
for _ in range(int(input())):
n, d = map(int, input().split())
a = [0] + list(map(int, input().split()))
ans = 0
for i in range(1, n+1):
ans += (a[i] <= d) != (a[i-1] <= d)
print(ans)