完成strStr() 函数

题目原型：

Implement strStr().

Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack.

    public String strStr(String haystack, String needle) {
        if(needle.length()>haystack.length())
        	return null;
        if(needle.equals("")||needle.length()==0)
        	return haystack;
        int i,j,first = 0;
        int start = 0;
        for(i=0,j=0;i<haystack.length()&&j<needle.length();)
        {
        	if(j==0)
        		start = i;
        	char ch1 = haystack.charAt(i);
        	char ch2 = needle.charAt(j);
        	if(ch1!=ch2)
        	{
        		i = start+1;
        		j = 0;
        	}
        	else
        	{
        		if(j==0)
            		first = i;
        		i++;
        		j++;
        	}
        }
        
        if(j==needle.length())
        	return haystack.substring(first);
        else
        	return null;
    }

完成strStr() 函数,布布扣,bubuko.com

完成strStr() 函数

原文：http://blog.csdn.net/cow__sky/article/details/20067759