[28] Implement strStr()

https://leetcode.com/problems/implement-strstr/description/

• algorithms
• Easy (30.44%)
• Source Code: 28.implement-strstr.py
• Total Accepted: 408.8K
• Total Submissions: 1.3M
• Testcase Example: '"hello"\n"ll"'

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
        """
        return haystack.find(needle)