python-algorithms/algorithms/strings/contain_string.py at master · ilyvsc/python-algorithms · GitHub

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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

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

"""

def contain_string(haystack, needle):

if len(needle) == 0:

return 0

if len(needle) > len(haystack):

return -1

for i in range(len(haystack)):

if len(haystack) - i < len(needle):

return -1

if haystack[i:i+len(needle)] == needle:

return i

return -1

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