LeetCode:Length of Last Word

题目链接

Given a string s consists of upper/lower-case alphabets and empty space characters

' '

, return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example,
Given s =

"Hello World"

,
return

5

.

借助strlen函数，相当于遍历两遍字符串 本文地址

class Solution {
public:
int lengthOfLastWord(const char *s) {
if(s == NULL)return 0;
int len = strlen(s), i, res = 0;
for(i = len-1; i >= 0 && s[i] == ' '; i--);//从尾部开始找到第一个非空格字符
for(; i >= 0 && s[i] != ' '; i--)res++;
return res;
}
};

遍历一遍字符串

class Solution {
public:
int lengthOfLastWord(const char *s) {
if(s == NULL)return 0;
int res = 0, cnt = 0;
for(; *s != '\0'; s++)
{
if(*s == ' ')
{
if(cnt != 0)
res = cnt;
cnt = 0;
}
else cnt++;
}
return cnt == 0 ? res : cnt;
}
};

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