[LeetCode] Length of Last Word 字符串查找

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.

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String

算法逻辑：

1. 排除最后的空格
2. index 从后往前查第一个空格。
3. 返回长度。

 1 #include <iostream>
 2 #include <cstring>
 3 using namespace std;
 4
 5
 6 class Solution {
 7 public:
 8     int lengthOfLastWord(const char *s) {
 9         int n = strlen(s);
10         if(n <1)    return 0;
11         int idx=n-1;
12         while(idx>=0&&s[idx]==‘ ‘)  idx--;
13         n = idx+1;
14         while(idx>=0){
15             if (s[idx]==‘ ‘)  break;
16             idx --;
17         }
18 //        if(idx<0)   return 0;
19         return n - idx -1;
20     }
21 };
22
23 int main()
24 {
25     char s[] = " 12   ";
26     Solution sol;
27     cout<<sol.lengthOfLastWord(s)<<endl;
28     return 0;
29 }