leetcode 第3题【无重复字符的最长子串】C语言

int lengthOfLongestSubstring(char * s)
{
    char *tail = s, *head = s;  
    int max = 0; 
    while (*tail)  
    {
        for (char *cur = head; cur < tail; cur++)
            if (*cur == *tail) 
            {
                head = cur + 1; 
                break;
            }
        if(tail-head+1>max)  
        {
            max=tail-head+1; 
        }
        tail++; 
    }
    return max;
}

知识点：字符串、指针、循环体