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Problem · String

Find First Unique 🍉

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Problem statement

Amazon Web Services is experimenting with optimizing search queries based on the location of the first unique character in a search. You have been asked to help test the query your team has created to ensure it works as designed. A unique character is one which appears only once in a string. Given a string consisting of lowercase English letters only, return the index of the first occurrence of a unique character in the string using 1-based indexing. If the string does not contain any unique character, return -1.

Function

findFirstUnique(s: String) → int

Complete the function findFirstUnique in the editor below.

findFirstUnique has the following parameter(s):

  • string s: a string

Returns

int: either the 1-based index or -1

Examples

Example 1

s = "statistics"return = 3
The unique characters are [a, c] among which a occurs first. Using 1-based indexing, it is at index 3.

Constraints

  • 1 <= len of s <= 105
  • The string s consists of lowercase English letters only.

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    public int findFirstUnique(String s) {
  // write your code here
}
    s"statistics"
    expected3
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