mirror of
https://github.com/prdlk/leetcode.git
synced 2026-11-02 13:12:44 +00:00
51 lines
1.0 KiB
Plaintext
51 lines
1.0 KiB
Plaintext
---
|
|
title: LC-387
|
|
description: First Unique Character in a String
|
|
---
|
|
|
|
## Examples
|
|
|
|
| Input | Output |
|
|
| ---------------- | ------ |
|
|
| `"leetcode"` | `0` |
|
|
| `"loveleetcode"` | `2` |
|
|
| `"aabb"` | `-1` |
|
|
|
|
## Hints
|
|
|
|
<Accordion type="single">
|
|
<AccordionItem title="Constraints">
|
|
Constraints:
|
|
• `1 <= s.length <= 10^5`
|
|
• `s` consists of only lowercase English letters.
|
|
</AccordionItem>
|
|
<AccordionItem title="Problem Statement">
|
|
Given a string `s`, find the first non-repeating character in it and return its index.
|
|
If it does not exist, return `-1`.
|
|
</AccordionItem>
|
|
</Accordion>
|
|
|
|
## Solution
|
|
|
|
```js
|
|
/**
|
|
* @param {string} s
|
|
* @return {number}
|
|
*/
|
|
|
|
var firstUniqChar = function (s) {
|
|
// Default for Hammer
|
|
const freq = {};
|
|
for (let c of s) freq[c] = (freq[c] || 0) + 1;
|
|
|
|
// Problem Specific
|
|
// Loop the ORIGINAL string — we want an index, so no sorting
|
|
for (let i = 0; i < s.length; i++) {
|
|
if (freq[s[i]] === 1) {
|
|
return i;
|
|
}
|
|
}
|
|
return -1;
|
|
};
|
|
```
|