Find The Index Of The First Occurence In A String

Problem

• 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.

Go Solution

func strStr(haystack string, needle string) int {
  i:= 0
  for len(needle) <= len(haystack) - i {
    if needle == haystack[i: i+ len(needle)] {
      return i
    }
    i++
  }
  return -1  
}

Performance

• Runtime beats: 100%
• Memory beats: 50%

Complexity

• Time: O(n)
• Space: O(n)