(LeetCode) Implement strStr()

Implement strStr()

  • 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

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

Example 2

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

Example 3

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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
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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.