Solution For Interview Question: First Not Repeating Character | Asked By Amazon
First Non-Repeating Character is another interview question that has been asked by Amazon and several companies. Here you have to find first occurrence of aa non repeating character from a given string. You can solve in codesignal, leetcode and many other places. But if you are looking for a different solution than yours, here's how I solved it.
There are similar problems that can be solved with this same approach
- Given a string, find the first non-repeating character and return the index
- First Unique Character in a String and return the index
Given a string
s consisting of small English letters, find and return the first instance of a non-repeating character in it. If there is no such character, return
s = "abacabad", the output should be
firstNotRepeatingCharacter(s) = 'c'.
- There are
2non-repeating characters in the string:
csince it appears in the string first.
s = "abacabaabacaba", the output should be
firstNotRepeatingCharacter(s) = '_'.
- There are no characters in this string that do not repeat.
- First create a map of the occurrence count for each item
- In second loop we check which item was existed only once
Complexity: O(2N) = O(N)