LeetCode: Length of Last Word

Tingmei

于 2012-10-04 21:19:46 发布

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分类专栏： C++ 算法文章标签： character function class null

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本文介绍了一种使用C++实现的方法，该方法能够计算给定字符串中最后一个单词的长度。通过从字符串的末尾开始遍历并跳过空格，此方法有效地找到了最后一个单词并返回其长度。

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Problem:

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.

从后向前遍历。

class Solution {
public:
    int lengthOfLastWord(const char *s) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (s == NULL) return 0;
        int nlen = strlen(s);
        int count = 0;
        int i = nlen - 1;
        while (i >= 0 && s[i] == ' ')
            --i;
        if (i == -1) return 0;
        while (i >= 0 && s[i] != ' ')
        {
            ++count;
            --i;
        }
        return count;
    }
};