(LeetCode) 28. Implement strStr()

Implement strStr()

• Explore : Interview > Top Interveiw Questions > Easy Collection
• 분류 : String
• 난이도 : Easy

Problem

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().

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 * 10^4
• haystack and needle consist of only lower-case English characters.

Solution

Exapnder

class Solution {
    fun strStr(haystack: String, needle: String): Int {
        if (!haystack.contains(needle)) {
            return -1
        }
        return haystack.indexOf(needle)
    }
}

Point of Thinking

• haystack에 포함되어있지 않으면 -1
• 포함되어있으면 indexOf()값 반환하면 Accepted.