[leetcode] 344. Reverse String

原题:

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"]

 

思路:

c++代码实现:

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