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62 lines
1.2 KiB
Plaintext
62 lines
1.2 KiB
Plaintext
---
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title: '344. Reverse String'
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description: Write a function that reverses a string. The input string is given as an array of characters s
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sidebar:
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label: 'Reverse String'
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badge: 'Easy'
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---
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<Badge variant="accent">Two Pointers</Badge>
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:::warning
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You must do this by modifying the input array in-place with O(1) extra memory.
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:::
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### Example 1:
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- Input: `s = ["h","e","l","l","o"]`
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- Output: `["o","l","l","e","h"]`
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### Example 2:
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- Input: `s = ["H","a","n","n","a","h"]`
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- Output: `["h","a","n","n","a","H"]`
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### Constraints:
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- `1 <= s.length <= 10^5`
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- `s[i]` is a printable ascii character.
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## Approach
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```mermaid
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flowchart TD
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S(["reverseString(s)"]) --> I["i = 0, j = s.length - 1"]
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I --> W{"i < j?"}
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W -- no --> E(["done — s was reversed in place, nothing returned"])
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W -- yes --> A["swap s[i] and s[j]"]
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A --> B["i++; j--"]
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B --> W
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```
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## Solution
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```js
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/**
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* @param {character[]} s
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* @return {void} Do not return anything, modify s in-place instead.
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*/
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var reverseString = function(s) {
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let i = 0;
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let j = s.length - 1;
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while (i < j) {
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[s[i], s[j]] = [s[j], s[i]];
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j--;
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i++;
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}
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};
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```
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## Explanation
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<YouTube id="_d0T_2Lk2qA" title="Reverse String - 3 Ways - Leetcode 344 - Python" />
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