LeetCode028 Implement strStr()

原创于 2018-04-13 22:43:56 发布 · 135 阅读

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本文介绍了一个字符串匹配的问题，并提供了一个Python实现的方法。通过内置函数或双循环来查找子串首次出现的位置。

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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().

一道字符串匹配问题，python自带函数直接就可以解决。或者用双循环去寻找。

class Solution(object):
    def strStr(self, haystack, needle):
        """
        :type haystack: str
        :type needle: str
        :rtype: int
        """
        if needle in haystack:
            return haystack.index(needle)
        else:
            return -1