g0001_0100.s0028_implement_strstr

Class Solution

java.lang.Object

g0001_0100.s0028_implement_strstr.Solution

public class Solution
extends Object

28 - Implement strStr().

Easy

Implement strStr().

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()](https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#indexOf(java.lang.String)).

Example 1:

Input: haystack = “hello”, needle = “ll”

Output: 2

Example 2:

Input: haystack = “aaaaa”, needle = “bba”

Output: -1

Example 3:

Input: haystack = "“, needle = ”"

Output: 0

Constraints:

• 0 <= haystack.length, needle.length <= 5 * 104
• haystack and needle consist of only lower-case English characters.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	strStr(String haystack, String needle)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

strStr

public int strStr(String haystack,
                  String needle)