717. 1-bit and 2-bit Characters

Problem

We have two special characters:

• The first character can be represented by one bit 0.

• The second character can be represented by two bits (10 or 11).

Given a binary array bits that ends with 0, return true if the last character must be a one-bit character.

  Example 1:

Input: bits = [1,0,0]
Output: true
Explanation: The only way to decode it is two-bit character and one-bit character.
So the last character is one-bit character.

Example 2:

Input: bits = [1,1,1,0]
Output: false
Explanation: The only way to decode it is two-bit character and two-bit character.
So the last character is not one-bit character.

  Constraints:

• 1 <= bits.length <= 1000

• bits[i] is either 0 or 1.

Solution (Java)

class Solution {
    public boolean isOneBitCharacter(int[] arr) {
        int i = 0;
        while (i < arr.length - 1) {
            i = (arr[i] == 1) ? i + 2 : i + 1;
        }
        return (i == arr.length - 1);
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).