28. implement strstr()

Posted on |

o— layout : post title : “28. Implement strStr()” category : algorithm[LeetCode] tags: [LeetCode] —

  • Source : Link
  • Author : Han
  • Date : 2022-02-24

Problems

Implement strStr().

Return the index of the first occurrence of needle in haystack, or -1 if needleis not part of haystack.

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().

Example 1:

1
2
3
Input: haystack = "hello", needle = "ll"
Output: 2

Example 2:

1
2
3
Input: haystack = "aaaaa", needle = "bba"
Output: -1

Example 3:

1
2
Input: haystack = "", needle = ""
Output: 0

Solution

1
2
3
4
5
class Solution {
    fun strStr(haystack: String, needle: String): Int {
        return haystack.indexOf(needle)
    }
}