数据结构算法操作试题(C++/Python)——实现strStr()

class Solution(object):
    def strStr(self, haystack, needle):
        """
        :type haystack: str
        :type needle: str
        :rtype: int
        """
        if not haystack and not needle: return 0
        if haystack == needle: return 0
        lenNeedle = len(needle)
        for i in range(len(haystack) - lenNeedle + 1):
            if haystack[i : i + lenNeedle] == needle:return i
        return -1