【LeetCode】Algorithm 21～30：28

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前言

本系列博客为平时刷LeetCode的记录，每十道题一篇博客，持续更新，所有代码详见GitHub：https://github.com/roguesir/LeetCode-Algorithm

28. Implement strStr()

Implement strStr().
Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Example 1:

Input: haystack = "hello", needle = "ll"
Output: 2
Example 2:

Input: haystack = "aaaaa", needle = "bba"
Output: -1
Clarification:

What should we return when needle is an empty string? This is a great question to ask during an interview.
For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C’s strstr() and Java’s indexOf().

class Solution(object):
    def strStr(self, haystack, needle):
        """
        :type haystack: str
        :type needle: str
        :rtype: int
        """
        if len(haystack) == 0 and len(needle) == 0:
            return 0
        if needle in haystack:
            for i in range(len(haystack)):
                if haystack[i: i+len(needle)] == needle:
                    return i
        else:
            return -1

• 更新时间：2019-01-27