Implement strStr() java solution

 Implement strStr() java solution

Implement strStr().

Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is 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:

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

Example 2:

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

 

Constraints:

• 1 <= haystack.length, needle.length <= 104
• haystack and needle consist of only lowercase English characters.

Solution:

class Solution {

    public int strStr(String haystack, String needle) {

     if(needle=="")

         return 0;

     if(haystack.contains(needle))

         return haystack.indexOf(needle);

        else

            return -1;

    }

}

also read: Determine if String Halves Are Alike java solution