LeetCode Easy: 28. Implement strStr()

一、题目

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

二、思路

首先我想到的就是python中特有的切片功能，遍历给定的 haystack ，然后与needle进行匹配，考虑鲁棒性当needle长度小于haystack的长度，返回-1.

三、代码

#coding:utf-8
def strStr(haystack, needle):
    """
    :type haystack: str
    :type needle: str
    :rtype: int
    """

    if len(needle)>len(haystack):
        return -1
    else:
        for i in range((len(haystack)-len(needle)+1)):
            if needle == haystack[i:i+len(needle):1]:
                print(i)
                return i
        return -1

if __name__ == '__main__':
    a = "hello"
    b = 'dl'
    strStr(a,b)

　　

niasd