dustfree's blog
0%

1-bit and 2-bit Characters

Posted on In ,

Question

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).

Now given a string represented by several bits. Return whether the last character must be a one-bit character or not. The given string will always end with a zero.

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.

Solution

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
public boolean isOneBitCharacter(int[] bits) {
    return check(0,bits);
}

public boolean check(int index, int[] bits) {
    if (index >= bits.length) {
        return false;
    }
    if (index == bits.length-1) {
        return true;
    }
    if (index == bits.length-2) {
        if (bits[index] == 0) {
            return true;
        }else {
            return false;
        }
    }
    
    if (bits[index] == 1) {
        return check(index+2,bits);
    }else {
        return check(index+1,bits);
    }
}