Leetcode刷题记录[java]——717 1-bit and 2-bit Characters

一、前言

 

二、题717 1-bit and 2-bit Characters

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.

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.

Note:

• 1 <= len(bits) <= 1000.
• bits[i] is always 0 or 1.

 

三、解题思路

　　遍历数组，至倒数第二位数，遍历规则是遇0加一，遇1加二，若数组以0结尾，则i=n-1；若以10结尾，则i=n。

class Solution {
    public boolean isOneBitCharacter(int[] bits) {
        
        //solution one
        int n = bits.length, i = 0;
        while(i < n - 1) {
            if (bits[i] == 0) i++;
            else i += 2;
        }
        return i == n - 1;
     
    }
}