[LeetCode]Length of Last Word

原创于 2013-05-29 19:43:09 发布 · 2.1k 阅读

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本文介绍了一种使用C++处理字符串的方法，特别是如何计算最后一个单词的长度。通过两个不同的实现方式，展示了如何遍历字符串并识别单词边界，最终返回最后一个单词的长度。

class Solution {
//be careful with the edge case "  ", "a  ", "a"
public:
	int lengthOfLastWord(const char *s) {
		// Start typing your C/C++ solution below
		// DO NOT write int main() function
		bool hasWordBegin = false;
		int wordBegin = 0;
		int wordEnd = 0;

		const char* p = s;
		int step = 0;
		while (true)
		{
			char nowChracter = *(p+step);
			if (nowChracter == '\0')
			{
				if (true == hasWordBegin)
					wordEnd = step;
				break;
			}
			if(nowChracter == ' ')
			{
				if (true == hasWordBegin)
					wordEnd = step;
				hasWordBegin = false;
			}
			else 
			{
				if(false == hasWordBegin)
					wordBegin = step;
				hasWordBegin = true;
			}
			step++;
		}
		int len = wordEnd-wordBegin;
		return len < 0 ? 0 : len;
	}
};

second time

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 ans = 0;
        while(*s != '\0')
        {
            if(*s != ' ')
            {
                int curLen = 0;
                while(*s != '\0' && *s != ' ') s++, curLen++;
                ans = curLen;
            }
            else s++;
        }
        
        return ans;
    }
};