LeetCode [344] Reverse String

Write a function that reverses a string. The input string is given as an array of characters char[].

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

You may assume all the characters consist of printable ascii characters.

Example 1:

Input: ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]

Example 2:

Input: ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]

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class Solution { public: void reverseString(vector<char>& s) { int i = 0, j = s.size()-1; while (i < j) { swap(s[i++], s[j--]); } } };