1-bit and 2-bit Characters
描述:
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.
思路:
有两个数,一个用0表示,一个用10或11表示。判断给定字符串的最后一个数是否是一位的。
分情况讨论,若字符串长度大于2则从头遍历,标准是遇0就到下一位,遇1则中间跳一位到下一位,如果恰好还剩两位且倒数第二位为0则true,否则false;如果还剩一位则必然为true。还剩下长度为2和1的情况分别写if-else讨论。
问题:
一开始测试用例不通过是只考虑了大于2的情况,但是少考虑了剩下的情况。应该全面考虑问题的各种可能。
感觉这样分情况讨论还是过于繁琐了点,应该有更简洁的办法。
代码:
bool isOneBitCharacter(int* bits, int bitsSize) {
int count=bitsSize;
int i=0;
if(count>2){
for(;count>2;){
if(bits[i]==0){
i++;
count--;
}
else{
i=i+2;
count=count-2;
}
}
if(count==2){
if(bits[bitsSize-2]==0)
return true;
else return false;
}
else
return true;
}
else
if(count==1){
return true;
}
else
if(bits[bitsSize-2]==0)
return true;
else return false;
}