[LeetCode]1-bit and 2-bit Characters 1位和2位字符

链接https://leetcode.com/problems/1-bit-and-2-bit-characters/description/

难度:Easy

题目:717. 1-bit and 2-bit 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:

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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:

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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.

翻译:给定两种字符,一种用1位的0表示,另一种用2位10或者11表示。现在给出一个由很多位字符表示的字符串,判断最后一位是不是1位字符。

思路:从头到尾遍历,如果该位数字为1,则向后前进两位,否则前进1位,循环的条件是i < n-1,即留出最后一位,所以当循环退出后,当i正好停留在n-1上,说明最后一位是单独分割开的。

参考代码

Java

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