def hackerlandRadioTransmitters(x, k): x = sorted(set(x)) count = 0 next_start = -float('inf')

for pos, val in enumerate(x):

    if val < next_start:
        continue

    for rg in range(k, -1, -1):
        if pos + rg < len(x) and val + k >= x[pos+rg]:
            next_start = x[pos+rg] + k + 1
            count += 1
            break

return count