Question
Formatted question description: https://leetcode.ca/all/344.html
344 Reverse String
Write a function that takes a string as input and returns the string reversed.
Example:
Given s = "hello", return "olleh".
@tag-string
@tag-2pointers
Algorithm
Go from both ends to the middle while swapping characters on both sides.
Code
Java
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public class Reverse_String { class Solution { public void reverseString(char[] s) { int l = 0; int r = s.length - 1; while (l < r) { char tmp = s[l]; s[l] = s[r]; s[r] = tmp; l++; r--; } } } class Solution_cheat { public String reverseString(String input) { StringBuilder s = new StringBuilder(input); s.reverse(); return s.toString(); } } }
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// OJ: https://leetcode.com/problems/reverse-string/ // Time: O(N) // Space: O(1) class Solution { public: void reverseString(vector<char>& s) { int i = 0, j = s.size() - 1; while (i < j) swap(s[i++], s[j--]); } };
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class Solution(object): def reverseString(self, s): """ :type s: str :rtype: str """ return s[::-1]