Ghost Detect

Ghost Detect

In the northern waters, sailors say they’ve seen Ghost Ship patrolling the waters. Nobody can see the other ships after they witness the Ghost Ship. This causes a problem: how do they distinguish a normal ship from the ghost ship in such dense fog? We can use a locator program for this.

For a normal ship, reflected signals have the same duration. So you wait for three signals and if they have the same durations, then we are safe because the ship is normal. If you see any difference - we’d better to run away, because that’s the Ghost Ship.

Let's look at some examples:
- The number on the locator is 21. It's "10101" in binary form and we see 3 signals with 1 second duration each. This is a normal ship.
- The number is 1587. The binary form is "11000110011” and we see 3 signals with 2 seconds duration but with various pauses. It's ok.
- The number is 3687. The binary form - "111001100111” and we see 3 signals. Two signals with 3 seconds duration and one with 2 seconds. It's a good idea to run away.

We have one more suggestion for this challenge. This is a code golf mission and your main goal is to make your code as short as possible (200 is absolute maximum, the less - the better).

Input: An integer (int).

Output: Is it a normal ship or not as a logic value (bool).

Examples:

assert recognize(21) == True
assert recognize(1587) == True
assert recognize(3687) == False

How it’s used: This is an example of the simple pattern recognition in text, and discrete signals.

Preconditions:

  • 21 ≤ number ≤ 1057222719;
  • There are three signal only in each test.