LeetCode 筆記 - Implement strStr()

class Solution:
    def strStr(self, haystack: str, needle: str) -> int:
        
        if not haystack or not needle:
            return 0
        
        main_length = len(haystack)
        check_length = len(needle)
        
        if main_length == 1:
            return 0
        
        for i in range(main_length):
            if haystack[i:i + check_length] == needle:
                return i
        
        return -1