028-implement-strstr.py

"""
Problem Link: https://leetcode.com/problems/implement-strstr/description/

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 needle == ""or needle == haystack: return 0
        l = len(needle)
        for i in range(0,(len(haystack)-l+1)):
            if haystack[i:i+l] == needle:
                return i
            print(haystack[i:i+l])
        return -1