Length of Last Word

最新推荐文章于 2025-09-06 17:22:57 发布

原创最新推荐文章于 2025-09-06 17:22:57 发布 · 456 阅读

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#leetcode

针对LeetCode上的Length of Last Word问题，介绍了从后向前遍历字符串的方法来计算最后一个单词的长度，并提供了C++实现代码。

Length of Last Word

Total Accepted: 50713 Total Submissions: 180895 My Submissions

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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思路：这一题曾经艾力跟我出过，当时我想的好简单然后好蠢，还打算从前往后进行计算。。后来虽然知道从后往前效率更高，但是没有考虑各种输入的情况，比如说字符串是“a“，” “等，今天又做了一遍，WA了n久，终于过了。。。

附上代码：

class Solution {
public:
    int lengthOfLastWord(string s) {
       int len=s.length();
       if(len==0) return 0;
       int num=0,j;
       for(int i=len-1;i>=0;i--)
       {
           num=0;
           if(isalpha(s[i]))
           {
              for(j=i;j>=0;j--)
              {
                 if(s[j]!=' ')
                    num++;
                 if(s[j]==' ')
                    break;
              }
              return num;
           }
           else
              continue;
       }
    }
};