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warmup10 min

First Unique Character in a String

First Unique Character in a String

Given a string s, return the index of the first character that appears exactly once. If there is no such character, return -1. Two passes: count all characters, then find the first with a count of 1.

firstUniqChar("leetcode");   // 0  ('l')
firstUniqChar("loveleetcode"); // 2  ('v')
firstUniqChar("aabb");       // -1

Run your code to see results.

Stuck? This challenge exercises:

javascript.data-structures