Reverse String

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344.Reverse String

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

You must do this by modifying the input array in-place with O(1) extra memory.

Example 1:

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

Example 2:

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

时间复杂度：O(n/2)

空间复杂度：O(1)

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class Solution {
public:
    void reverseString(vector<char>& s) {
        int s_size = s.size();
        for (int i = 0; i < s_size / 2; i++) {
            swap(s[i], s[s_size - i - 1]);
        }
    }
};